Lectured by Bien Eli Nillos, MDReference: Gray’s Anatomy

The Human Muscles

Table of Contents

Introduction to Muscles (next slide)Part One: Muscles of the Thorax, Shoulders and BackPart Two: Muscles of the Abdomen, Upper Arm, Forea

rm and HandPart Three: Muscles of the Pelvis, Perineum and Lowe

r Extremities

MUSCLES

vary extremely in their form (long, broad, short, etc)

considerable variation in the arrangement of the fibers of certain muscles with reference to the tendons to which they are attached

fibers are parallel or not quite parallel, but slightly curved or fibers are convergent (broad base) or the origin and insertion are not in the same plane, but the plane of the line of origin intersects that of the line of insertion or fibers are oblique and converge (unipennate) or oblique fibers converge to both sides of a central tendon (bipennate) or fibers are arranged in curved bundles in one or more planes

Origin versus Insertion

origin is meant to imply its more fixed or central attachment

insertion is the movable point on which the force of the muscle is applied

the origin is absolutely fixed in only a small number of muscles, such as those of the face which are attached by one extremity to immovable bones

in the greater number, the muscle can be made to act from either extremity

In the dissection of the muscles, attention should be directed to the exact origin, insertion,and actions of each, and to its more important relations with surrounding parts

When it comes to muscle action: One (or more) muscle of the combination is the chief moving force (prime movers); when this muscle passes over more than one joint other muscles (synergic muscles) come into play to inhibit the movements not required.

a third set of muscles (fixation muscles) fix the limb

Application of Knowing Muscle Action

By a consideration of the action of the muscles, the surgeon is able to explain the causes of displacement in various forms of fracture, and the causes which produce distortion in various deformities, and, consequently, to adopt appropriate treatment in each case

How muscles are named

 (1) from their location, (ex. Tibialis, Radialis, Ulnaris,

Peroneus)(2) from their direction, (ex. Rectus abdominis, Obliqui

capitis, Transversus abdominis)(3) from their uses, (ex. Flexors, Extensors, Abductors,

etc.) (4) from their shape, (ex. Deltoideus, Rhomboideus) (5) from the number of their divisions, (ex. Biceps

and Triceps)(6) from their points of attachment, (ex.

Sternocleidomastoideus, Sternohyoideus, Sternothyreoideus.)

Overview of the Muscles

Surface Anatomy of Thorax

Pectoralis Major

a thick, fan-shaped muscle, situated at the upper and forepart of the chest.

arises from the anterior surface of the sternal half of the clavicle; from half the breadth of the anterior surface of the sternum, as low down as the attachment of the cartilage of the sixth or seventh rib; from the cartilages of all the true ribs, with the exception, frequently, of the first or seventh, or both, and from the aponeurosis of the Obliquus externus abdominis

inserted into the crest of the greater tubercle of the humerus

Pectoralis Minor

a thin, triangular muscle, situated at the upper part of the thorax, beneath the Pectoralis major.

arises from the upper margins and outer surfaces of the third, fourth, and fifth ribs, near their cartilage and from the aponeuroses covering the Intercostalis; the fibers pass upward and lateralward and converge to form a flat tendon,

inserted into the medial border and upper surface of the coracoid process of the scapula

Subclavius

a small triangular muscle, placed between the clavicle and the first rib.

arises by a short, thick tendon from the first rib and its cartilage at their junction, in front of the costoclavicular ligament; the fleshy fibers proceed obliquely upward and lateralward

inserted into the groove on the under surface of the clavicle between the costoclavicular and conoid ligaments.

Serratus Anterior

Is a thin muscular sheet, situated between the ribs and the scapula at the upper and lateral part of the chest.

arises by fleshy digitations from the outer surfaces and superior borders of the upper eight or nine ribs, and from the aponeuroses covering the intervening Intercostales. Each digitation (except the first) arises from the corresponding rib;

reach the vertebral border of the scapula, The lower four slips interdigitate at their origins with the

upper five slips of the External Oblique Muscles

Nerve Supply

The Pectoralis major is supplied by the medial and lateral anterior thoracic nerves.

The Pectoralis minor receives its fibers from the eighth cervical and first thoracic nerves through the medial anterior thoracic nerve.

The Subclavius is suplied by a filament from the fifth and sixth cervical nerves.

The Serratus anterior is supplied by the long thoracic, which is derived from the fifth, sixth, and seventh cervical nerves

The Shoulder

The Deltoids

 is a large, thick, triangular muscle, which covers the shoulder-joint in front, behind, and laterally.

arises from the anterior border and upper surface of the lateral third of the clavicle; from the lateral margin and upper surface of the acromion, and from the lower lip of the posterior border of the spine of the scapula, as far back as the triangular surface at its medial end.

they unite in a thick tendon, which is inserted into the deltoid prominence on the middle of the lateral side of the body of the humerus. At its insertion the muscle gives off an expansion to the deep fascia of the arm

Subscapularis

a large triangular muscle which fills the subscapular fossa arises from its medial two-thirds and from the lower two-

thirds of the groove on the axillary border of the bone. Some fibers arise from tendinous laminæ which intersect the muscle and are attached to ridges on the bone; others from an aponeurosis, which separates the muscle from the Teres major and the long head of the Triceps brachii.

The fibers pass lateralward, and, gradually converging, end in a tendon which is inserted into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint. 

Supraspinatus

occupies the whole of the supraspinatous fossa arising from its medial two-thirds, and from the

strong supraspinatous fascia. The muscular fibers converge to a tendon, which crosses the upper part of the shoulder-joint

inserted into the highest of the three impressions on the greater tubercle of the humerus; the tendon is intimately adherent to the capsule of the shoulder-joint.

Infraspinatus

a thick triangular muscle, which occupies the chief part of the infraspinatous fossa.

arises by fleshy fibers from its medial two-thirds, and by tendinous fibers from the ridges on its surface; it also arises from the infraspinatous fascia which covers it, and separates it from the Teres major and minor.

inserted into the middle impression on the greater tubercle of the humerus.

Teres Minor

a narrow, elongated musclearises from the dorsal surface of the axillary border of

the scapula for the upper two-thirds of its extent, and from two aponeurotic laminæ, one of which separates it from the Infraspinatus, the other from the Teres major.

inserted into the lowest of the three impressions on the greater tubercle of the humerus; the lowest fibers are inserted directly into the humerus immediately below this impression.

Teres Major

 is a thick but somewhat flattened muscle, arises from the oval area on the dorsal

surface of the inferior angle of the scapula, and from the fibrous septa interposed between the muscle and the Teres minor and Infraspinatus;

inserted into the crest of the lesser tubercle of the humerus.

The Upper Back Muscles

Trapezius

flat, triangular muscle, covering the upper and back part of the neck and shoulders.

arises from the external occipital protuberance and the medial third of the superior nuchal line of the occipital bone, from the ligamentum nuchæ, the spinous process of the seventh cervical, and the spinous processes of all the thoracic vertebræ, and from the corresponding portion of the supraspinal ligament.

The superior fibers are inserted into the posterior border of the lateral third of the clavicle; the middle fibers into the medial margin of the acromion, and into the superior lip of the posterior border of the spine of the scapula

Latissimus Dorsi

a triangular, flat muscle, which covers the lumbar region and the lower half of the thoracic region,

It arises by tendinous fibers from the spinous processes of the lower six thoracic vertebræ and from the posterior layer of the lumbodorsal fascia  by which it is attached to the spines of the lumbar and sacral vertebræ, to the supraspinal ligament, and to the posterior part of the crest of the ilium.

It also arises from the external lip of the crest of the ilium lateral to the margin of the Sacrospinalis, and from the three or four lower ribs by fleshy digitations,

inserted into the bottom of the intertubercular groove of the humerus;

The lateral margin of the Latissimus dorsi is separated below from the External Oblique by a small triangular interval, the lumbar triangle of Petit, the base of which is formed by the iliac crest, and its floor by the Internal Oblique.

Another triangle is situated behind the scapula. It is bounded above by the Trapezius, below by the Latissimus dorsi, and laterally by the vertebral border of the scapula; the floor is partly formed by the Rhomboideus major. The space is therefore known as the triangle of ausculation.

Rhomboid Major

arises by tendinous fibers from the spinous processes of the second, third, fourth, and fifth thoracic vertebræ and the supraspinal ligament

inserted into a narrow tendinous arch, attached above to the lower part of the triangular surface at the root of the spine of the scapula; below to the inferior angle, the arch being connected to the vertebral border by a thin membrane.

Rhomboid Minor

arises from the lower part of the ligamentum nuchæ and from the spinous processes of the seventh cervical and first thoracic vertebræ.

inserted into the base of the triangular smooth surface at the root of the spine of the scapula, and is usually separated from the Rhomboideus major by a slight interval, but the adjacent margins of the two muscles are occasionally united.

Levator Scapulae

is situated at the back and side of the neck. arises by tendinous slips from the transverse

processes of the atlas and axis and from the posterior tubercles of the transverse processes of the third and fourth cervical vertebræ.

inserted into the vertebral border of the scapula, between the medial angle and the triangular smooth surface at the root of the spine.

END OF PART ONE

Lab WorkSheet No. 1 For Midterms In a tabular form, write the origin, insertion, action and

nerve supply of the following muscles:1. Biceps2. Triceps3. Brachialis4. Coracobrachialis5. Brachioradialis6. Pronator Teres7. Flexor Carpi radialis8. Palmaris Longus9. Flexor carpi ulnaris10. Flexor digitorum sublimis11. Flexor digitorum profundus12. Flexor pollicis longus13. Pronator Quadratus14. Abductor pollicis brevis15. Flexor pollicis brevis

Lab Worksheet No. 1 Midterms Draw the torso and label the following muscles.

Identify the following surface landmarks in your drawing. Color as much as possible to identify each muscle:

1. External Oblique2. Internal Oblique3. Transversus abdominis4. Rectus abdominis5. Pyramidalis6. Linea alba7. Linea Semilunaris8. Linea Semicircularis9. Inguinal Ligament10. Serratus anterior

Part Two: The Human Muscles

Abdomen and Upper Extremities

QUIZ # 1

1-3. 3 origins of the Pectoral Major muscle4. insertion of the deltoid muscle5-8. the 4 rotator cuff muscles9. muscle that gives the posterior axillary

fold10. nerve supply of the serratus anterior

muscle

The Abdominals

External Oblique

is the largest and the most superficial of the three flat muscles in this region

 arises, by eight fleshy digitations, from the external surfaces and inferior borders of the lower eight ribs; these digitations are arranged in an oblique line which runs downward and backward

inserted into linea alba, pubic crest & tubercle, anterior superior iliac spine & anterior half of iliac crest

Aponeurosis of the External Oblique

a thin but strong membranous structure, the fibers of which are directed downward and medialward. It is joined with that of the opposite muscle along the middle line, and covers the whole of the front of the abdomen

In the middle line, it interlaces with the aponeurosis of the opposite muscle, forming the linea alba, which extends from the xiphoid process to the symphysis pubis

  That portion of the aponeurosis which extends between the anterior superior iliac spine and the pubic tubercle is a thick band, folded inward, and continuous below with the fascia lata; it is called the inguinal ligament.

  In the aponeurosis of the external oblique, immediately above the crest of the pubis, is a triangular opening, the superficial inguinal ring, formed by a separation of the fibers of the aponeurosis in this location

Internal Oblique

an irregularly quadrilateral form, and situated at the lateral and anterior parts of the abdomen

arises, by fleshy fibers, from the lateral half of the grooved upper surface of the inguinal ligament, from the anterior two-thirds of the middle lip of the iliac crest, and from the posterior lamella of the lumbodorsal fascia

Inserts into lower 3 or 4 ribs, linea alba, pubic crest

The Cremaster

is a thin muscular layer, composed of a number of fasciculi which arise from the middle of the inguinal ligament where its fibers are continuous with those of the Internal Oblique and also occasionally with the Transversus.

It passes along the lateral side of the spermatic cord, descends with it through the subcutaneous inguinal ring upon the front and sides of the cord, and forms a series of loops which differ in thickness and length in different subjects

The Cremasteric Reflex

elicited by lightly stroking the superior and medial part of the thigh

The normal response is a contraction of the cremaster muscle that pulls up the scrotum and testis on the side stroked

reflex utilizes sensory and motor fibers of the genitofemoral nerve

Transversus Abdominis

the most internal of the flat muscles of the abdomen

arises from lower 6 ribs, thoracolumbar fascia, anterior 3/4 of the iliac crest, lateral 1/3 of inguinal ligament

Inserts into linea alba, pubic crest and pecten of the pubis

Transversalis Fascia

 thin aponeurotic membrane which lies between the inner surface of the Transversus abdominis and the extraperitoneal fascia

The spermatic cord in the male and the round ligament of the uterus in the female pass through the transversalis fascia at a spot called the deep inguinal ring.

Deep Inguinal Ring

situated in the transversalis fascia, midway between the anterior superior iliac spine and the symphysis pubis, and about 1.25 cm. above the inguinal ligament

oval form, the long axis of the oval being vertical; it varies in size in different subjects, and is much larger in the male than in the female

The Inguinal Canal

Anterior Wall - aponeurosis of external oblique , aponeurosis of internal oblique (lateral third of canal only), superficial inguinal ring (medial third of canal only)

Posterior Wall - transversalis fascia, conjoint tendon (medial third of canal only), deep inguinal ring (lateral third of canal only)

The Inguinal Canal

Roof - internal oblique and transversus abdominis

Floor - inguinal ligament, lacunar ligament (medial third of canal only), iliopubic tract (lateral third of canal only)

MNEMONICS – MALT (Muscles, Aponeurosis, Ligaments, Tendons)

The Inguinal Canal

contains the spermatic cord and the ilioinguinal nerve in the male, and the round ligament of the uterus and the ilioinguinal nerve in the female

It is an oblique canal about 4 cm. long, slanting downward and medialward, and placed parallel with and a little above the inguinal ligament;

it extends from the deep inguinal ring to the superficial inguinal ring

Rectus Abdominis

 a long flat muscle, which extends along the whole length of the front of the abdomen, and is separated from its fellow of the opposite side by the linea alba. It is much broader, but thinner, above than below

Arises from pubis and the pubic symphysis Inserted to xiphoid process of the sternum and

costal cartilages 5-7

The Rectus is crossed by fibrous bands, three in number, which are named the tendinous inscriptions

Rectus is enclosed in a sheath formed by the aponeuroses of the Oblique and Transversus

The Arcuate Line

a horizontal line that demarcates the lower limit of the posterior layer of the rectus sheath. It is also where the inferior epigastric vessels perforates the rectus abdominus

Quadratus Lumborum

 irregularly quadrilateral in shape, and broader below than above

 arises by aponeurotic fibers from the iliolumbar ligament and the adjacent portion of the iliac crest for about 5 cm.,

inserted into the lower border of the last rib for about half its length, and by four small tendons into the apices of the transverse processes of the upper four lumbar vertebræ

The Muscles of the Upper Extremity

Biceps

 a long fusiform muscle, placed on the front of the arm Origins are - short head: tip of the coracoid process of

the scapula long head: supraglenoid tubercle of the scapula

Inserted at tuberosity of the radius

Triceps

 situated on the back of the arm, extending the entire length of the dorsal surface of the humerus

Origins: long head: infraglenoid tubercle of the scapula; lateral head: posterolateral humerus & lateral intermuscular septum; medial head: posteromedial surface of the inferior 1/2 of the humerus

Insertion: olecranon process of the ulna

Coracobrachialis

smallest of the three muscles in this region, is situated at the upper and medial part of the arm

Origin: coracoid process of the scapula Insertion: medial side of the humerus at mid-

shaft

Brachialis

covers the front of the elbow-joint and the lower half of the humerus

Origin: anterior surface of the lower one-half of the humerus and the associated intermuscular septa

Insertion: coronoid process of the ulna

ForearmAnterior Group vs. Posterior Group

Anterior Forearm Muscles

Superficial vs. DeepAll Flexors, Pronators are in the Anterior

Forearm, including the Palmaris Longus

Posterior Forearm MusclesSuperficial vs. Deep

All Extensors, Supinator, Brachioradialis, Anconeus and Abductor Pollicis Longus

The Muscles of the Hand

subdivided into three groups: (1) those of the thumb, which occupy the radial

side and produce the thenar eminence; (2) those of the little finger, which occupy the

ulnar side and give rise to the hypothenar eminence; 

(3) those in the middle of the palm and between the metacarpal bones.

Lateral Volar Muscles

Abductor pollicis brevis.Flexor pollicis brevis.Opponens pollicis.Adductor pollicis (oblique).Adductor pollicis (transverse).

Medial Volar Muscles

Palmaris brevis.Flexor digiti quinti

brevis.Abductor digiti quinti.Opponens digiti

quinti.

The Intermediate Muscles

Lumbricales

Interossei

End of Part Two

Quiz 2

1 – 2 Origin of Biceps3- 5 Origin of Triceps6. Anterior wall of inguinal canal7. Posterior wall of inguinal canal8. Roof of the Inguinal canal9. Floor of the Inguinal canal10. Which compartment of the forearm is the

extensor pollicis longus?

Muscles of the Pelvis and Perineum

Pre-test (technically, my first pre-test ever for this SY)

1. It is the longest muscle in the body2. Which of the anal sphincters is voluntary?3. What muscle compresses the crus penis, and

retards the return of the blood through the veins, and thus serves to maintain the organ erect?

4. - 7. Four muscles which comprise the Quadriceps Femoris

8. - 10. Three Hamstring muscles

The Pelvic Muscles

The muscles within the pelvis may be divided into two groups: (1) the Obturator internus and the Piriformis, which are muscles of the lower extremity, (2) the Levator ani and the Coccygeus, which together form the pelvic diaphragm and are associated with the pelvic viscera

The Pelvic Fascia

fascia of the Obturator internus covers the pelvic surface of, and is attached around the margin of the origin of, the muscle

The internal pudendal vessels and pudendal nerve cross the pelvic surface of the Obturator internus and are enclosed in a special canal—Alcock’s canal—formed by the obturator fascia

The fascia of the Piriformis is very thin and is attached to the front of the sacrum and the sides of the greater sciatic foramen; it is prolonged on the muscle into the gluteal region.

At its sacral attachment around the margins of the anterior sacral foramina it comes into intimate association with and ensheathes the nerves emerging from these foramina.

The sacral nerves are frequently described as lying behind the fascia

Levator ani

is a broad, thin muscle, situated on the side of the pelvis. It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity. It supports the viscera in this cavity, and surrounds the various structures which pass through it

Levator Ani

Origin: posterior surface of the body of the pubis, fascia of the obturator internus m. (arcus tendineus levator ani), ischial spine

Insertion: anococcygeal raphe and coccyx Action: elevates the pelvic floor The combination of puborectalis, pubococcygeus &

iliococcygeus is the levator ani muscle; coccygeus and levator ani combined form the pelvic diaphragm

The anterior portion is occasionally separated from the rest of the muscle by connective tissue. From this circumstance, as well as from its peculiar relation with the prostate, which it supports as in a sling, it has been described as a distinct muscle, under the name of Levator prostatæ

Action: elevates the prostate

Coccygeus

a triangular plane of muscular and tendinous fibers

Origin: ischial spineInsertion: side of the coccyx and lower

sacrumAction: elevates the pelvic floor

Corrugator Cutis Ani

Around the anus is a thin stratum of involuntary muscular fiber, which radiates from the orifice. Medially the fibers fade off into the submucous tissue, while laterally they blend with the true skin. By its contraction it raises the skin into ridges around the margin of the anus.

External Anal Sphincter

Origin: perineal body or central tendinous point of the perineum

Insertion: encircles the anal canal; superficial fibers attach to the coccyx

skeletal (voluntary) muscle s considered part of the pelvic diaphragm

Internal Anal Sphincter

Origin: encircles the anal canal Insertion: encircles the anal canal smooth muscle (involuntary

Transversus perinæi superficialis (MALE)

a narrow muscular slip, which passes more or less transversely across the perineal space in front of the anus

arises by tendinous fibers from the inner and forepart of the tuberosity of the ischium

inserted into the central tendinous point of the perineum, joining in this situation with the muscle of the opposite side, with the Sphincter ani externus behind, and with the Bulbocavernosus in front

Transversus perinæi superficialis in the female is a narrow muscular slip, which arises by a small tendon from the inner and forepart of the tuberosity of the ischium, and is inserted into the central tendinous point of the perineum, joining in this situation with the muscle of the opposite side, the Sphincter ani externus behind, and the Bulbocavernosus in front.

Central Tendinous Point of the Perineum

a fibrous point in the middle line of the perineum, between the urethra and anus, and about 1.25 cm. in front of the latter.

At this point six muscles converge and are attached:Sphincter ani externus, the Bulbocavernosus,

the two Transversi perinæi superficiales, and the anterior fibers of the Levatores ani

(Two Bitches Like Slapping ass)

Bulbocavernosus

placed in the middle line of the perineum, in front of the anus. It consists of two symmetrical parts, united along the median line by a tendinous raphé

Origin: central tendinous point of the perineum and from the median raphé

Insertion: inferior fascia of the urogenital diaphragm, encircle the bulb and adjacent parts of the corpus cavernosum urethræ and join with the fibers of the opposite side

Bulbocavernosus in the female surrounds the orifice of the vagina. It covers the lateral parts of the vestibular bulbs, and is attached posteriorly to the central tendinous point of the perineum, where it blends with the Sphincter ani externus. Its fibers pass forward on either side of the vagina to be inserted into the corpora cavernosa clitoridis, a fasciculus crossing over the body of the organ so as to compress the deep dorsal vein.

Ischiocavernosus

covers the crus penis. It is an elongated muscle, broader in the middle than at

either end, and situated on the lateral boundary of the perineum.

arises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus penis; and from the rami of the pubis and ischium on either side of the crus.  

inserted into the sides and under surface of the crus penis.

The Ischiocavernosus compresses the crus penis, and retards the return of the blood through the veins, and thus serves to maintain the organ erect.

Ischiocavernosus (Erector clitoridis) in the female is smaller than the corresponding muscle in the male. It covers the unattached surface of the crus clitoridis. It is an elongated muscle, broader at the middle than at either end, and situated on the side of the lateral boundary of the perineum. Itarises by tendinous and fleshy fibers from the inner surface of the tuberosity of the ischium, behind the crus clitoridis; from the surface of the crus; and from the adjacent portion of the ramus of the ischium. From these points fleshy fibers succeed, and end in an aponeurosis, which is inserted into the sides and under surface of the crus clitoridis.

There are two main categories of female genital mutilation, clitoridectomy, and infibulation.

Clitoridectomy is the removal of the clitoris. This is done to decrease a woman's ability to achieve orgasm, in the hopes to keep her from having sex.

Infibulation if the removal of the clitoris, the labia minora, and the labia majora. What remains of the labia majora is sewn shut, leaving a small opening only so large as to allow the passage of urine and menstrual blood. The procedure is often used as a means of protecting the virginity of the woman, and to control her sexual desires. 

The Muscles of the Lower Extremities

 I. Muscles of the Iliac Region. II. Muscles of the ThighIII. Muscles of the Leg. IV. Muscles of the Foot.

Psoas Major

 long fusiform muscle placed on the side of the lumbar region of the vertebral column and brim of the lesser pelvis

Origin: bodies and transverse processes of lumbar vertebrae

Insertion: lesser trochanter of femur (with iliacus) via iliopsoas tendon

the genitofemoral nerve pierces the anterior surface of the psoas major

Psoas Minor

a long slender muscle, placed in front of the Psoas major

Origin: bodies of the T12 & L1 vertebrae Insertion: iliopubic eminence at the line of

junction of the ilium and the superior pubic ramus

absent in 40% of cases

Iliacus

 a flat, triangular muscle, which fills the iliac fossa

Origin: iliac fossa and iliac crest; ala of sacrum

Insertion: lesser trochanter of the femur inserts in company with the psoas major m.

via the iliopsoas tendon

Anterior Thigh Muscles

SartoriusQuadriceps Femoris (Rectus Femoris, Vastus

Lateralis, Vastus Medialis, Vastus Intermedius)

Articularis genu

Satorius

longest muscle in the body, is narrow and ribbon-like

Origin: anterior superior iliac spine Insetion: medial surface of the tibia (pes

anserinus) sartorius means "tailor"; its actions put the lower

limb in the traditional cross-legged seated position of a tailor

Quadriceps Femoris

Rectus femoris is situated in the middle of the front of the thigh; it is fusiform in shape, and its superficial fibers are arranged in a bipenniform manner

Origin: straight head- anterior inferior iliac spine; reflected head - above the superior rim of the acetabulum

Insertion: patella and tibial tuberosity (via the patellar ligament)

Quadriceps Femoris

The Vastus Lateralis is the largest part of the Quadriceps femoris.

Origin: lateral intermuscular septum, lateral lip of the linea aspera and the gluteal tuberosity

Insertion: patella and medial patellar retinaculum

Quadriceps Femoris

The Vastus MedialisOrigin: medial intermuscular septum, medial

lip of the linea aspera Insertion: patella and medial patellar

retinaculum

Quadriceps Femoris

The Vastus IntermediusOrigin: anterior and lateral surface of the

femur Insertion: patella

Gracilis

the most superficial muscle on the medial side of the thigh

Origin: pubic symphysis and the inferior pubic ramus

Insertion: medial surface of the tibia (via pes anserinus)

the pes anserinus is the common insertion of the gracilis, sartorius, and semitendinosus muscles

Pectineus

a flat, quadrangular muscle, situated at the anterior part of the upper and medial aspect of the thigh

Origin: pecten of the pubis Insertion: pectineal line of the femur

Adductor Longus

the most superficial of the three Adductores, is a triangular muscle, lying in the same plane as the Pectineus

Origin: medial portion of the superior pubic ramus

Insertion: linea aspera of the femur

Adductor Brevis

situated immediately behind the two preceding muscles. It is somewhat triangular in form

Origin: inferior pubic ramus Insertion: pectineal line and linea aspera (deep to the

pectineus and adductor longus mm.) anterior and posterior divisions of the obturator

nerve lie on the anterior and posterior surfaces of adductor brevis

Adductor Magnus

 large triangular muscle, situated on the medial side of the thigh

Origin: ischiopubic ramus and ischial tuberosity Insertion: linea aspera of the femur; the

ischiocondylar part inserts on the adductor tubercle of the femur

the ischiocondylar part of adductor magnus is a hamstring muscle by embryonic origin and action, so it is innervated by the tibial nerve

The Muscles of the Gluteal RegionGlutæus maximus.Glutæus medius Glutæus minimus Obturator internus.Gemellus superior.Gemellus inferior.Tensor fasciæ latæ.Quadratus femoris.Piriformis.Obturator externus.

The Hamstrings

Biceps femorisSemitendinosusSemimembranos

us

Biceps Femoris

situated on the posterior and lateral aspect of the thigh

Origin: long head - ischial tuberosity; short head - lateral lip of the linea aspera

Insertion: head of fibula and lateral condyle of the tibia

Semitendinosus

remarkable for the great length of its tendon of insertion, is situated at the posterior and medial aspect of the thigh

Origin: lower, medial surface of ischial tuberosity (common tendon with biceps femoris m.)

Insertion: medial surface of tibia (via pes anserinus)

Semimembranosus

so called from its membranous tendon of origin, is situated at the back and medial side of the thigh

Origin: upper, outer surface of the ischial tuberosity

Insertion: medial condyle of the tibia

Muscles of the Leg

three groups: anterior, posterior, and lateral.

Anterior

Tibialis anterior.Extensor digitorum longus.Extensor hallucis longus.Peronæus tertius.

Posterior Group

Superficial versus DeepSuperficial muscles –

Gastrocnemius, Soleus, Plantaris (GPS)

Deep muscles – Popliteus, Flexor digitorum longus, Flexor hallucis longus, Tibialis posterior.

Lateral Group

Peronæus longus

Peronæus brevis

“Shoot for the moon.  Even if you miss, you'll land among the stars.” ~Les Brown

Lab Worksheet No. 2 (Midterms)

A. Draw the Axilla. In Tabular Form, identify its boundaries and contents

B. Draw the Antecubital Fossa. In Tabular Form, Identify its Boundaries and contents.

C. Draw the Popliteal Fossa. In Tabular Form, identify its boundaries and contents.

D. Draw the Triangles of the neck. In your drawing, identify the boundaries of the triangles. In a Tabular form, identify the contents of each triangle.