Palm of Hand and Sole of Foot Flashcards
Which property of the palm of the hand enabled gripping ?
The skin is firmly bound to the underlying palmar aponeurosis, which contains a series of potential spaces and layers of fascia and muscle (including thenar and hypothenar muscles)
What is the PALMAR APONEUROSIS ?
Triangular condensation of deep fascia
Where do vessels, nerves, and long flexor tendons lie, relative to the palmar aponeurosis ?
Deep to it
Describe more features of the palmar aponeurosis.
- Thickens as 4 longitudinal bands (with connections) that continue with the fibrous flexor sheaths
- Sends septae to the 3rd and 5th metacarpals to create compartments and potential spaces (e.g. midpalmar space, thenar space.
How is the midpalmar space continuous with the forearm ?
Via the carpal tunnel.
What are the thenar muscles ?
Where are they located ?
How are they innervated ?
- Abductor pollicis brevis (median nerve)
- Opponens pollicis (median nerve)
- Flexor pollicis brevis (median and ulnar nerve)
- Adductor pollicis (ulnar nerve)
Located around the thumb
What are the hypothenar muscles ?
Where are they located ?
How are they innervated ?
- Abductor digiti minimi
- Flexor digiti minimi brevis
- Opponens digiti minimi
- Palmaris brevis
Located around the 5th finger
All supplied by the ulnar nerve
Are thenar and hypothenar muscles intrinsic or extrinsic ?
Intrisinc
How does the thenar muscles help movements of the thumb ?
Thenar muscles give precision to thumb movements, esp. for opposition
How many lumbrical muscles are there in one hand ?
How many interosseal muscles ?
4 3 (palmar interossei) + 4 (dorsal interossei) = 7
What is the origin and insertion of lumbrical muscles ?
Origin: tendons of deep flexors
Insertion: extensor expansions
What is the origin and insertion of palmar interosseal muscles ?
Origin: metacarpals
Insertion: extensor expansions
What is the origin and insertion of dorsal interosseal muscles ?
Origin: metacarpals
Insertion: extensor expansions
What movements are performed by the palmar interosseal muscles ?
Adduction of fingers (PAD)
Flexion of MCP joint
Extension of IP joint
What movements are performed by the dorsal interosseal muscles ?
Abduction of fingers (DAB)
Flexion of MCP joint
Extension of IP joint
What are the lumbrical, palmar interosseal, and dorsal interosseal muscles respectively innervated by ?
Lumbrical: Lateral 2 by Median nerve, medial 2 by Ulnar Nerve
Palmar Interosseal: Ulnar nerve
Dorsal Interosseal: Ulnar nerve
Acting together, what movements can lumbricals and interosseal muscles bring about ?
Flexion of MCP joint
Extension of IP joint
Which root supplies the small muscles of the hand ?
T1 (through either ulnar and/or median)
Describe the location of the extensor retinaculum, relative to surrounding structures.
Between radius, styloid process of ulna, triquetrum and pisiform
What is the function of the extensor retinaculum ?
Holds the extensor tendons in place, in synovial sheaths against the posterior aspects of the radius and ulna.
How many synovial canals run under the extensor retinaculum?
Name the muscles going through each synovial canal under the extensor retinaculum, lateral to medial.
6
- Abductor Pollicis Longus with Extensor Pollicis Brevis
- Extensor Carpi Radialis Longus and Brevis
- Extensor Pollicis Longus
- Extensor Digitorum and Extensor Indicis
- Extensor Digiti Minimi
- Extensor Carpi Ulnaris
What is the flexor retinaculum ? Describe its layers.
A band of antebrachial fascia
Superficial palmar carpal ligament and Deep transverse carpal ligament