Anatomy Tables - Extensor Compartment of the Forearm, Deep Hand, Wrist and Hand Joints

Joints and Associated Structures of the Hand

Joint or structure Description Significance
palmar aponeurosis
(N459, TG2-33, Practical)
a thick aponeurotic layer overlying the central compartment of the palm the palmaris longus inserts into it (Greek, aponeurosis = a broad, flat nerve)
fibrous flexor digital sheaths
(N462, TG2-34)
fibrous tunnels formed on the palmar surfaces of the phalanges transmits the flexor tendons
flexor retinaculum
(N460, TG2-34, Practical)
a ligament stretching from the scaphoid and trapezeum to the hamate and pisiform, deep and slightly distal to the palmar carpal ligament forms the carpal tunnel (Latin, retinaculum = a band or halter)
carpal tunnel
(N461, TG2-36, Practical)
formed by the carpal bones and the flexor retinaculum transmits the flexor pollicis longus, flexor digitorum superficialis & profundus, and the median n. (Latin, carpus = the wrist)
thenar compartment
(N460, N462, TG2-34, TG2-36)
the lateral compartment of the palmar surface of the hand contains the abductor pollicis brevis laterally, flexor pollicis brevis medially, and opponens pollicis deeply (Greek, thenar = the palm of the hand)
hypothenar compartment
(N460, N462, TG2-34, TG2-36)
the medial compartment of the palmar surface of the hand contains the abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi
central compartment
(N462, TG2-36)
the central compartment of the palmar surface of the hand contains the flexor tendons, the lumbricals, the superficial palmar arterial arch, and common palmar digital branches of the median and ulnar nerves
adductor-interosseous compartment
(N462, TG2-36)
the deepest compartment of the palmar surface of the hand contains the adductor pollicis, 3 palmar interossei, 4 dorsal interossei, the deep palmar arterial arch, and the deep branch of the ulnar n. (Latin, adduct = to bring towards,inter = between + os = bone)
radial bursa
(N462)
the synovial sheath of the tendon of flexor pollicis longus
ulnar bursa
(N462, TG2-34)
the synovial sheath surrounding the tendons of flexor digitorum superficialis and profundus it usually extends into the fibrous flexor sheath of the fifth digit
vincula
(N464, TG2-45)
slips of synovial membrane extending between phalanges and flexor tendons vincula conduct neurovascular bundles to the flexor tendons (Latin, vincula = to bind)

Muscles of the Hand

Muscle Origin Insertion Action Innervation Blood Supply Notes Image
abductor digiti minimi (hand)
(N461, N465, TG2-35)
pisiform base of the proximal phalanx of the 5th digit on its ulnar side abducts the 5th digit deep branch of the ulnar nerve ulnar a. abductor digiti minimi, flexor digiti minimi brevis, and opponens digiti minimi are located in the hypothenar compartment of the hand
abductor pollicis brevis
(N465, TG2-34)
flexor retinaculum, scaphoid, trapezium base of the proximal phalanx of the first digit abducts thumb recurrent branch of median nerve superficial palmar br. of the radial a. abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis are located in the thenar compartment of the hand (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
adductor pollicis
(N461, N465, TG2-35)
oblique head: capitate and base of the 2nd and 3rd metacarpals; transverse head: shaft of the 3rd metacarpal base of the proximal phalanx of the thumb adducts the thumb ulnar nerve, deep branch deep palmar arterial arch deep palmar arch and deep ulnar nerve pass between the two heads of adductor pollicis, which is in the adductor-interosseous compartment (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
extensor pollicis brevis interosseous membrane and the posterior surface of the distal radius base of the proximal phalanx of the thumb extends the thumb at the metacarpophalangeal joint deep radial nerve posterior interosseous a the tendons of extensor pollicis brevis and abductor pollicis longus make the lateral border of the anatomical snuffbox, in which the radial arterial pulse can be felt (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
flexor digiti minimi brevis (hand)
(N461, N465, TG2-34)
hook of hamate & the flexor retinaculum proximal phalanx of the 5th digit flexes the carpometacarpal and metacarpophalangeal joints of the 5th digit ulnar nerve, deep branch ulnar a. flexor digiti minimi brevis, abductor digiti minimi, and opponens digiti minimi are in the hypothenar compartment of the hand
flexor pollicis brevis
(N465, TG2-34)
flexor retinaculum, trapezium proximal phalanx of the 1st digit flexes the carpometacarpal and metacarpophalangeal joints of the thumb recurrent branch of the median nerve superficial palmar br. of the radial a. flexor pollicis brevis, abductor pollicis brevis, and opponens pollicis are the three muscles of the thenar compartment of the hand(Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
flexor pollicis longus
(N461, TG2-25)
anterior surface of radius and interosseous membrane base of the distal phalanx of the thumb flexes the metacarpophalangeal and interphalangeal joints of the thumb median nerve anterior interosseous a. the tendon of flexor pollicis longus passes through the carpal tunnel with the other long digital flexor tendons and the median nerve (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
interosseous, dorsal (hand)
(N465, TG2-35)
four muscles, each arising from two adjacent metacarpal shafts base of the proximal phalanx and the extensor expansion on lateral side of the 2nd digit, lateral & medial sides of the 3rd digit, and medial side of the 4th digit flex the metacarpophalangeal joint, extend the proximal and distal interphalangeal joints of digits 2-4, abduct digits 2-4 (abduction of digits in the hand is defined as movement away from the midline of the 3rd digit) ulnar nerve, deep branch dorsal and palmar metacarpal aa. bipennate muscles; remember DAB & PAD - Dorsal interosseous mm. ABduct and Palmar interosseous mm. ADduct - then you can figure out where they must insert to cause these actions (Latin, inter = between + os = bone)
interosseous, palmar
(N465, TG2-35)
three (or four) muscles, arising from the palmar surface of the shafts of metacarpals 1, 2, 4, & 5 (the 1st palmar interosseous is often fused with the adductor pollicis m.) base of the proximal phalanx and extensor expansion of the medial side of digits 1 & 2, and lateral side of digits 4 & 5 flexes the metacarpophalangeal, extends proximal and distal interphalangeal joints and adducts digits 1, 2, 4, & 5 (adduction of the digits of the hand is in reference to the midline of the 3rd digit) ulnar nerve, deep branch palmar metacarpal aa. unipennate muscles; remember PAD & DAB: Palmar interossei ADduct and Dorsal interossei ABduct, and you will be able to figure out where they must insert (Latin, inter = between + os = bone)
lumbrical (hand)
(N463, TG2-34)
flexor digitorum profundus tendons of digits 2-5 extensor expansion on the radial side of the proximal phalanx of digits 2-5 flex the metacarpophalangeal joints, extend the proximal and distal interphalangeal joints of digits 2-5 median nerve (radial 2) via palmar digital nerves & ulnar nerve (ulnar 2) via deep branch superficial palmar arterial arch lumbricals, (lumbricus is latin for "worm") arise from the profundus tendons and have the same pattern of innervation as does the profundus muscle (ulnar and median nn. split the task equally) (Latin, lumbricus = earthworm)
opponens digiti minimi
(N461, N448, TG2-35)
hook of hamate and flexor retinaculum shaft of 5th metacarpal opposes the 5th digit ulnar nerve, deep branch ulnar a. opposition is a rotational movement of the 5th metacarpal around the long axis of its shaft; opponens digiti minimi, abductor digiti minimi, and flexor digiti minimi brevis are in the hypothenar compartment of the hand
opponens pollicis
(N465, TG2-35, Practical)
flexor retinaculum, trapezium shaft of 1st metacarpal opposes the thumb recurrent branch of median nerve superficial palmar branch of the radial a. opposition is a rotational movement of the 1st metacarpal around the long axis of its shaft; opponens pollicis, abductor pollicis brevis, and flexor pollicis brevis are in the thenar compartment of the hand (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
palmaris brevis
(N459, TG2-33)
fascia overlying the hypothenar eminence skin of the palm near the ulnar border of the hand draws the skin of the ulnar side of the hand toward the center of the palm superficial br. of the ulnar n. ulnar a. palmaris brevis improves the grasp

Arteries of the Hand

Artery Source Branches Supply Notes
arch, deep palmar
(N466, TG2-37A, TG2-37B, Practical)
radial a., deep br. of ulnar a. palmar metacarpal aa. (2nd-4th), perforating brs. deep palm, digits including the dorsum of the distal phalangeal segment deep palmar arterial arch receives the majority of its blood supply from the radial a.
arch, superficial palmar
(N466, TG2-37A, TG2-37B)
ulnar a., superficial palmar br. of the radial a. common palmar digital aa. (3) superficial palm, palmar surface of the digits excluding thumb, dorsum of the distal phalangeal segments of digits 2-5 superficial palmar arterial arch receives the majority of its blood supply from the ulnar a.
digital, common palmar
(N466, TG2-37A, TG2-37B)
superficial palmar arterial arch proper palmar digital aa. (2) palmar aspect two adjacent digits common palmar digital aa. anastomose with palmar metacarpal aa.
digital, proper palmar
(N466, TG2-37A, TG2-37B, Practical)
common palmar digital a. no named branches palmar aspect of each digit proper palmar digital aa. supply the dorsum of the distal phalangeal segment and nail bed
princeps pollicis
(N466, TG2-37, Practical)
radial a. two brs. to the thumb palmar aspect of the thumb including the dorsum of the distal phalangeal segment arteria princeps pollicis is similar in function to a proper digital aa.; this artery has a large pulse which can be felt when attempting to take the pulse of a patient - use fingers to feel for the patient's pulse (Latin, pollicis = the thumb or first finger from pollere, to be strong, because the thumb is stronger than other fingers)
radial
(N466, TG2-37, Practical1, Practical2)
brachial a. radial recurrent a., palmar carpal br., superficial palmar br., dorsal carpal br., 1st dorsal metacarpal a., princeps pollicis a., radialis indicis a., deep palmar arterial arch posterior elbow, posterior forearm, posterior hand, deep portion of palmar side of the hand, thumb radial a. provides the majority of blood supply to the deep palmar arterial arch; normally it arises at the level of the elbow but high branching of the brachial a. may result in the radial a. arising as proximal as the axilla
radialis indicis
(N466, TG2-37)
radial a. no named branches lateral (radial) side of the index finger arteria radialis indicis is equivalent to a proper digital a.
recurrent, anterior ulnar
(N466, TG2-37A, TG2-37B)
ulnar a. unnamed muscular brs. medial side of elbow and proximal ends of forearm flexor mm. anterior ulnar recurrent a. often arises in common with the posterior ulnar recurrent a. (Latin, ulna = elbow)
superficial ulnar
(N466, TG2-37A, TG2-37B)
ulnar a. no named branches palm continues as the superficial palmar arch (Latin, ulna = elbow)

Nerves of the Hand

Nerve Source Branches Motor Sensory Notes
digital, common palmar
(N466, TG2-38)
median n.; superficial br. of the ulnar n. proper palmar digital nn. sympathetic motor to the skin; motor nn. to the 1st & 2nd lumbrical mm. are carried on common palmar digital brs. of the median n. skin of the palmar surfaces of the adjacent sides of two digits the proper branches of these nerves also supply the dorsum of the tip of the digit (nail bed)
digital, dorsal radial n. no named branches sympathetic motor innervation to skin dorsal skin of the lateral 3 1/2 digits, except the nail bed the nail bed is supplied by palmar digital nn.
digital, proper palmar
(N466, TG2-38A, TG2-38B)
common palmar digital branches of the median n.; common palmar digital branches of the superficial br. of the ulnar n. no named branches sympathetic motor to the skin median: palmar skin and nail bed of digits 1-3 and the lateral side of 4th digit; ulnar: palmar and dorsal skin on medial side of the 4th digit and all of the 5th digit proper palmar digital nn. supply the dorsum of the tip of the digit (nail bed)
dorsal branch of the ulnar n.
(N476, TG2-49)
ulnar n. dorsal digital sympathetic motor innervation to skin skin of the dorsal surface of the medial 1 1/2 digits; skin of the medial side of the back of the hand dorsal branch of the ulnar n. emerges at the level of the ulnar styloid process (Latin, ulna = elbow)
median n.
(N475, TG2-48, Practical1, Practical2)
lateral and medial cords of the brachial plexus anterior interosseous n., palmar br., recurrent (motor) br., common palmar digital nn. (for digits 1-3) pronator teres m., flexor carpi radialis m., palmaris longus m., flexor digitorum superficialis m., flexor digitorum profundus m. (radial half), flexor pollicis longus m., pronator quadratus m., abductor pollicis brevis m., flexor pollicis brevis m., opponens pollicis m., lateral 2 lumbrical mm. skin of the radial half of the palm and palmar side of the lateral 3 1/2 digits (and nail bed for these digits) the median n. is motor to the flexor muscles of the forearm (except flexor carpi ulnaris and the medial 1/2 of the flexor digitorum profundus),the muscles of the thenar compartment and the lateral 2 lumbricals
recurrent br. of median n.
(N466, TG2-38, Practical)
median n. immediately distal to carpal tunnel none abductor pollicis brevis m., flexor pollicis brevis m., opponens pollicis m. none recurrent br. is also called the million dollar nerve
ulnar n.
(N466, TG2-37A, TG2-37B, Practical1, Practical2, Practical3)
medial cord of the brachial plexus (C8, T1) palmar cutaneous br., dorsal br., superficial and deep brs. flexor carpi ulnaris m., flexor digitorum profundus m. (ulnar half), abductor digiti minimi m., flexor digiti minimi brevis m., opponens digiti minimi m., ulnar 2 lumbrical mm., palmar and dorsal interosseous mm. skin of the medial side of the wrist and hand; skin of the medial 1 1/2 digits ulnar n. is motor to most of the muscles of the hand (Latin, ulna = elbow)

Clinical Terms

Term Definition
Dupuytren's contracture A progressive shortening, thickening, and fibrosis of the palmar fascia and aponeurosis. The fibrous degeneration of the longitudinal bands of the palmar aponeurosis on the medial side of the hand pulls the ring and little fingers into partial flexion at the MP and PIP joints. The contracture is frequently bilateral and is common in men older than 50 years; the cause is unknown, but evidence points to a hereditary disposition. Treatment involves excision of the fibrotic parts of the palmar fascia.
ulnar claw hand Ulnar nerve injury commonly occurs where the nerve passes posterior to the medial epicondyle of the humerus. The injury results when the posteromedial part of the elbow hits a hard surface, fracturing the medial epicondyle. Ulnar nerve injury causes extensive motor and sensory loss to the hand. Power of adduction is impaired, and when an attempt is made to make a fist the hand is drawn laterally by the flexor carpi radialis (which gets its nerve supply from the median nerve). Following ulnar nerve injury, patients have difficulty making a fist because they cannot flex their 4th and 5th digits at the distal interphalangeal joints. This characteristic appearance of the hand resulting from a distal lesion of the ulnar nerve is known as clawhand. (Latin, ulna = elbow)
carpal tunnel syndrome results from any lesion that significally reduces the size of the carpal tunnel. Fluid retention, infection, and excessive exercise of the fingers may cause swelling of the tendons or their synovial sheaths. Median nerve is the most sensitive structure in the carpal tunnel and therefore is the most affected. Median nerve has sensory branches to the lateral three and a half digits thus paresthesia (abnormal sensation), hypothesia (reduced sensation), or anesthesia (loss of sensation) may occur. Furthermore, the only motor branch of the median nerve is the recurrent branch which serves three thenar muscles. Continued compresion of the median nerve will lead to weakness of the abductor pollicis brevis and opponens pollicis. To relieve the symptoms, partial or complete surgical division of the flexor retinaculum (carpal tunnel release) may be necessary. Clinically this syndrome can be tested for by tapping on the carpal tunnel. If symptoms are elicited (positive Tinel's sign), the syndrome is likely.
ape hand a deformity marked by thumb movements being limited to flexion and extension in the plane of the palm due to the inability to oppose (and limited abduction of) the thumb. The recurrent (thenar) branch of the median nerve supplying the thenar muscles lies subcutaneously and may be severed by relatively minor lacerations involving the thenar eminence. Severence of this nerve paralyzes the thenar muscles, and the thumb loses much of its usefulness.
Allen's test Test for collateral circulation between radial and ulnar arteries or patency of them. The patient makes a tight fist expressing the blood from the hand. The examiner then compresses either the radial or ulnar artery and then has the patient open the hand. If the hand turns pinkish the connection between and both vessels are patent. If on opening the hand blood fails to return to palm and fingers, the non-compressed artery is occluded and there is no collateral circulation between the two.

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.

 

Updated: 31 Oct 2011