Anatomy of the HandArtwork & Research by Katie Moriarty

Surface of the Hand

Bones and Joints of the Hand

Bones of the Fingers

• Distal Phalanges: located on the top of the finger; each has a convex dorsal surface and a flat palmar surface; rough elevation provides support for the nail bed

• Middle Phalanges: located between the distal and proximal phalanges; does not exist on the thumb

• Proximal Phalanges: lie at the base of the finger; connect to the the metacarpals at the knuckle

Bones of the Hand

• Metacarpals: make up the knuckles of the hand; are the bones of the palm; long bone

• Carpals: connect the hand to forearm; are the bones of the wrist; facilitate positioning of the hand; consist of eight bones: hamate, pisiform, triquetrum, capitate, lunate, trapezoid, trapezium, and the scaphoid

Joints of the Hand

• Metacarpophalangeal joint: joints of the fingers when the fist is closed; connect the proximal phalanges to the metacarpals; synovial joint with the movements of extension, flexion, and abduction

• Interphalangeal joints: located between the phalanges; hinge joint with only the movements of flexion and extension; contains a fibrous capsule for extra stability and strength

• Basilar Joint: located at the base of the thumb; formed by a small bone in the wrist and the metacarpal of the thumb

Fingertip and Nail Complex

Fingertip and Nail Complex

• Sterile Matrix: commonly known as the nail bed; it extends from the lunula to the hyponychium; contains the blood vessels, nerves, and melanocytes

• Germinal Matrix: root of the fingernail; located mostly beneath the skin; forms most of the volume of the nail; only visible part is the edge of the germinal matrix (lunula)

• Lunula: white cresent shape structure in the germinal matrix• Eponychium: more commonly known as the cuticle; fuses

together the skin of the finger and the nail bed for a waterproof barrier.

• Nail Plate: this is the actual nail of a finger; composed of keratin; has a pink appearance due to the blood vessels beneath it

Muscles of the Hand

Muscles of the hand (as seen in drawing)

• First Dorsal Interossei: four muscles located in the back of the hand; act by spreading the index, middle, and ring fingers away from the hand as well as assist in flexion at the knuckle joints, and extension in the finger joints

• Adductor pollicis: functions to adduct the thumb; fan-shaped and flat; beneath the long flexor tendons and lumbrical muscles, but overlie the metacarpal bones

• Opponens pollicis: functions to oppose the thumb; small triangular muscle

Muscles of the Hand (as seen in drawing)

• Opponens Digiti Minimi: triangular muscle of the hand; functions to flex and laterally rotate the little finger; innervated by the deep branch of the ulnar nerve

• Flexor Digiti Minimi Brevis: flexes the little finger; a hypothenar muscle; also innervated by the deep branch of the ulnar nerve

The End!

Works Cited

• "Abductor Muscles and Their Function." Abductor Muscles and Their Function. N.p., n.d. Web. 30 Mar. 2013.

• "Basal Joint Arthritis." Orthopedic Specialists of Seattle. Orthopedic Specialists of Seattle, n.d. Web. 30 Mar. 2013.

• Brannan, Heather, MD. "Nail." About.com Dermatology. N.p., n.d. Web. 30 Mar. 2013. • "Carpal Bones." Mayo Clinic. Mayo Foundation for Medical Education and Research,

n.d. Web. 30 Mar. 2013. • De Lange, A. "Result Filters." National Center for Biotechnology Information. U.S.

National Library of Medicine, n.d. Web. 30 Mar. 2013. • Dery, Bernard. "Bones of the Hand." Bones of the Hand. N.p., n.d. Web. 30 Mar. 2013. • "Flexor Digiti Minimi Brevis (hand)." Wikipedia. Wikimedia Foundation, 15 Mar. 2013.

Web. 30 Mar. 2013. • " Hand Anatomy." Hand Anatomy. N.p., n.d. Web. 30 Mar. 2013.