HK - Anterior Forearm & Hand

IMPORTANT FOR THE PRACTICAL! We typically need to reflect _______ and trace the median nerve distally to view the anterior interosseous (AI) nerve – which muscle needs to be reflected?

Answer explanation

A) Carpal tunnel is a space that exists under/over the flexor retinaculum (type the right answer)

B) As the median nerve exits the carpal tunnel, it immediately gives a VERY SUPERFICIAL branch that travels backwards called the ________ - this is IMPORTANT FOR THE PRACTICAL!

Answer explanation

The recurrent branch of the median nerve kind of sneaks back posteriorly and innervates all three muscles associated with the thenar eminence (digit 1); AFO pollicis brevis

A) Palmaris longus inserts on the _______, a set of dense, triangular-shaped fascia located superficially immediately deep to the skin.

B) The ulnar nerve travels superficial/deep to palmaris brevis (Type 'deep' or 'superficial')

Answer explanation

Recall that palmaris brevis exists on the ULNAR aspect of the hand (digit 5/pinky finger)

I would kind of say this is an unfair question, but you have to think about in lab.

The ulnar nerve does travel DEEP to palmaris brevis - it is just that the superficial branch of the ulnar nerve innervates palmaris brevis (which is evident in dissection)

After travelling deep to palmaris brevis, the ulnar nerve divides into a superficial and deep branch

The superficial branch of the ulnar nerve ends cutaneously and carries cutaneous sensation back from the _____ digits in most individuals.

• medial 1 ½ (one and a half) digits

• lateral 1 ½ (one and a half) digits

• medial 3 ½ (three and a half) digits

• lateral 3 ½ (three and a half) digits

A) The ULNAR NERVE travels distally in the anterior compartment of the forearm deep to which muscle?

B) After piercing the hypothenar eminence, the deep branch of the ulnar nerve reappears on the deep (coconut) palm innervating the interosseus muscles and disappearing into _______.

A) The ​ (a)   innervates adductor pollicis and creeps (b)   the muscle to innervate it.

B) The recurrent branch of the median nerve is located ​ (c)  

• under
• deep branch of the ulnar nerve
• median nerve
• recurrent branch of the median nerve
• superficial branch of the ulnar nerve
• over
• anterior interosseous nerve
• superficially
• deep

Answer explanation

Where do the lumbrical muscles originate and insert? Please be as specific as you can. Also name their innervation and action...

Answer explanation

Origin: Tendons of flexor digitorum

profundus (palmar/anterior side)

Insertion: Extensor tendons (posterior/dorsal aspect of the palm)

Innervation of...

Lateral 2 lumbricals: Median nerve

Medial 2 lumbricals: Deep branch of ulnar

nerve

Action: Flexion at the metacarpophalangeal joint AND Extension at the interphalangeal joints

Where do the interosseous muscles originate and insert? Please be as specific as you can. Also name their innervation and all actions...

Answer explanation

Origin: Between the metacarpal bones

Insertion: Extensor tendons (posterior/dorsal aspect of the palm)

Innervation: Deep branch of ulnar

nerve

Action of...

Palmar Interossei: Adduction of the digits from the axial line/middle finger (3 of these muscles)

Dorsal Interossei: Abduction of the digits from the axial line/middle finger (4 of these muscles)

Both Interossei:

- Flexion at the metacarpophalangeal joint

- Extension at the interphalangeal joints

A) The _____ nerve exists between flexor digitorum profundus and flexor digitorum superficialis. In lab, it can sometimes be stuck on flexor digitorum superficialis as it sits deep to it.

B) Lumbrical muscles are located on the ulnar/radial/medial/lateral/thumb/pinky side of the long flexor tendons

Do not type the word 'nerve' for and choose only ONE word of the 6 for B (multiple correct answers will be accepted, but do not type multiple words)

Answer explanation

Categorize the following muscles in the anterior forearm to their innervation. Note that the anterior interosseus (AI) nerve is a branch of the median nerve.

Groups:

(a) Anterior interosseus (AI) nerve

,

(b) Median nerve: Superficial branches

,

(c) Ulnar Nerve

• Palmaris Longus

• Pronator Quadratus

• Lateral half of flexor digitorum profundus

• Medial half of flexor digitorum profundus

• Flexor Carpi Radialis

• Flexor Carpi Ulnaris

• Flexor Pollicis Longus

• Pronator Teres

• Flexor Digitorum Superficialis