Download The hand is comprised of intrinsic muscles, important nerves and

The hand is comprised of intrinsic muscles, important nerves and vessels (Jenkins, 1998,
p. 173). The muscles are divided into four compartments, thenar, hypothenar, central and
interosseus. The cadaver that I practiced and applied my dissection skills on is the cadaver on
tank #21. The region that I chose was the cadaver’s right hand. Prior to my dissection, I observed
that the extensor retinaculum was dissected off but a small region of the flexor retinaculum was
still exposed. The deep fascia, palmar aponeurosis, had also been dissected off, as well as the
palmaris brevis muscle. I noticed that the origins, carpal bones, were not exposed during my
dissection but I was familiar and able to palpate its location to understand its origin and
insertions, especially for the muscles of the thenar and hypothenar comparment.
The thenar compartment is located on the palmer surface of the hand, lateral
compartment of the hand, near the base of the thumb. The cadaver I dissected revealed the
muscles abductor pollicis brevis, flexor pollicis brevis and opponens pollicis. The muscle
abductor pollicis brevis originates from the carpal bones trapezium and scaphoid and the flexor
retinaculum. The muscle appeared thin and short. Its insertion is on the base of the proximal
phalanx of thumb. The abductor pollicis brevis is innervated by the median nerve. The abductor
pollicis brevis was cut but remained in its place to reveal the opponens pollicis. The muscle
flexor pollicis brevis originates from the flexor retinaculum, carpal bone trapezium and 1st
metacarpal. The muscle appeared short and fusiform. Its insertion is on the base of the proximal
phalanx of thumb. The flexor pollicis brevis is innervated by the median nerve. The last muscle
of the thenar compartment is the opponens pollicis and it is revealed beneath the abductor
pollicis brevis. The muscle opponens pollicis originates from the flexor retinaculum and carpal
bone trapezium. The muscle appeared flat and deep, compared to the other two muscles of the
thenar compartment. Its insertion is on the lateral border of the 1st metacarpal. The opponens
pollicis is innervated by the median nerve.
The hypothenar compartment is located on the palmer surface of the hand, medial
compartment of the hand, near the base of the small finger. The cadaver I dissected revealed the
muscles flexor digiti minimi and opponens digiti minimi. The cadaver did not reveal the
abductor digiti minimi. Prior to my dissection, I noticed it was already torn off. I was not able to
observe or reveal the muscle but I was able see it on other cadavers. The muscle appeared short
and fusiform. Its origins are the tendon of flexor carpi ulnaris and carpal bone pisiform. Its
insertion is the proximal phalanx of 5th digit. The abductor digiti minmi is innervated by the
median nerve. The muscle flexor digiti minimi originates from the hook of hamate and flexor
retinaculum. The muscle appeared short and fusiform. Its insertion is on the proximal phalanx of
5th digit. The flexor digiti minimi is innervated by the ulnar nerve. The muscle opponens digiti
minimi originates from the hook of hamate and flexor retinaculum. The muscle appeared flat and
deep, similar to the opponens pollicis, compared to the other two muscles of the hypothenar
compartment. Its insertion is on the medial border of 5th metacarpal. The opponens digiti minimi
is innervated by the ulnar nerve.
The central compartment is located on the center of the palmer surface of the hand. After
trying to apply my skills of dissection, I dissected too much and cut through majority of the
lumbrical muscles. The only muscle that is observable is lumbrical I which appeared slender and
“worm-like”. Prior to applying my dissection skills, I noticed that the muscle adductor pollicis
was not dissected well but both the transverse and oblique heads are still observable. The muscle
appeared fan-shaped when the transverse and oblique heads are held in place together. The
lumbrical muscles (I and II) originate from the lateral two tendons of flexor digitorum profundus.
The lumbrical muscles (III and IV) originate from the adjacent sides of medial three tendons of
flexor digitorum profundus. The lumbrical muscles I-V insert at the lateral bases of proximal
phalanx of digits II-V and the extensor expansion. The lumbricals I and II are innervated by the
median nerve and lumbricals III and IV are innervated by the ulnar nerve. The adductor pollicis,
transverse head, originates from the entire metacarpal III and the adductor pollicis, oblique head,
originates from the bases of metacarpals II-III and carpal bone capitates. The adductor pollicis
heads both insert at the base of the 1st phalanx of thumb. The adductor pollicis is innervated by
the ulnar nerve.
The last compartment of the hand is the interosseus compartment. The palmer interossei
muscles are located on palmer surfaces of the hand. The dorsal interossei muscles are located
between the metacarpals. All seven muscles appeared flat and short. After trying to apply my
skills of dissection, I believe I dissected too much and too deep. I think I also used the wrong
tools to dissect and did not probably handle them carefully enough. I was not able to observe or
reveal the three palmer interossei muscles. But, I did see and palpate the three palmer interossei
muscles on other cadavers and its origins are metacarpals II, IV and V. Its insertions are on the
1st phalanx of fingers II, IV and V and the extensor expansion. The three palmer interossei are
innervated by the ulnar nerve. After trying to apply my skills of dissection again, I believe I
dissected too much and too deep to one of the dorsal interossei muscles, III. Every other dorsal
interossei muscle is observable, revealed and dissected well. The dorsal interossei muscles
originate from the sides of adjacent metacarpals I-V. Its insertions are 1st phalanx of fingers II-V
and the extensor expansion. The dorsal interossei muscles are innervated by the ulnar nerve.
References:
Jenkins, David B. HOLLINSHEAD'S Functional Anatomy of the Limbs and Back. 7th ed.
Philadelphia: W.B Saunder's Company, 1998. Print.