Sievert: Anterior Hand, Joints of the upper limb and nerve lesions Flashcards
Are there intrinsic hand muscles in the dorsum of the hand?
No
The anterior hand can be divided into what two compartment muscles? What are the two muscles of the metacarpals and tendons of the hands?
thenar and hypothenar compartment muscles;
lumbricals and interossei
2 compartments beneath the palmar aponeurosis. Which goes to the thumb? Which goes to little finger?
thenar compartment (lateral to aponeurosis)** thumb hypothenar compartment (medial to aponeurosis) ** little finger
What are the three thenar muscles? What are the three hypothenar muscles?
Opponens pollicis Abductor pollicis brevis Flexor pollicis brevis; Opponens digiti minimi Abductor digiti minimi Flexor digiti minimi brevis;
A disease of the palmar fascia resulting in thickening and shortening of fibrous bands on the palmar surface of the hand and fingers
Dupuytren’s contracture
What nerve innervates the three thenar compartment muscles?
median nerve
Is the ADductor pollicis innervated by the median nerve?
No, it’s not a thenar compartment muscle
What nerve innervates the three hypothenar muscles?
ulnar nerve
What passes through the carpal tunnel?
9 tendons (4 tendons of the flexor digitorum profundus, 4 tendons of the flexor digitorum superficialis, flexor pollicis longus) and the medial nerve
Do the ulnar artery and nerve pass through the carpal tunnel?
No
Which two tendons of the flexor digitorum superficialis are most anterior??
tendons to digits 3&4
Which thenar muscle is most lateral? Which attaches to the base of the metacarpal?
abductor pollicis brevis; opponens pollicis
A strong flexor retinaculum that encompasses 9 tendons and the median nerve. Ulnar artery and nerve do not pass through it.
carpal tunnel
When there is compression of the carpal tunnel, what nerve are you worried about? What are the main side effects?
Median nerve; will cause weakness in the thumb (3 thenar muscles) and numbness in 3.5 digits!
(blank) are muscles in between the metacarpals. (blank) are muscles in between the long tendons.
interossei; lumbricals
The synovial tendon sheaths of digits 3, 4, and 5 can become infected and rupture. Where will the contents be released? What can this cause?
into the midpalmar space; rupture will cause adhesions of all of the tendons in that space, which causes everything to start binding up
If the synovial tendon sheath of digit 2 ruptures, where will the contents be released?
into the thenar space
The thumb is considered the first digit. The little finger is the fifth digit.
Ok.
Which 2 digits have synovial sheaths that tend not to rupture into the midpalmar or thenar spaces. Why? Where do they rupture instead? Is this more or less serious than a midpalmar/thenar rupture?
Tendon sheaths of 1 and 5 can become infected and rupture into the forearm, because their sheaths extend up into the forearm. A rupture here is not as serious!!
T/F: Tendon sheaths of 2,3+4 can become infected and rupture into the thenar (2) or midpalmar (3+4) space.
True
What holds the long flexor tendons tightly against the metacarpals and the phalanges? What band is on the proximal phalanx? What band is on the middle phalanx? What band is near the MP? The PIP? The DIP?
The fibrous digital sheaths; A2; A4; A1; A3; A5
odd ones are nearer the joints
As tendons pass through to attach to phalanges, they must be held down by dense CT bands. This protects from bowstringing. There are 5 (blank) bands that go over the top (A1-A5). There are also (blank) portions, which are much weaker. A2 and A4 are in the middle of the proximal and middle phalanx. 1, 3, and 5 are nearer the joints.
There is a synovial tendon sheath that covers the tendon.
Tendons don’t have a good blood supply, but get some supply from the inferior aspect via an extension of the synovial tendon sheath.
annular; cruciform
Where do lumbricals originate from? Where do they insert? What are they innervated by? Which side of the bone are they located on?
from the flexor digitorum profundus tendons; insert into the extensor hoods; innervated by median (2 on radial side) and ulnar nerves (2 on ulnar side); always on the RADIAL side
What is the action of the lumbricals?
flex MP joint; extend PIP and DIP (salute)
So, collectively what does the ulnar nerve supply?
Ulnar nerve supplies all intrinsic muscles of the hand EXCEPT for the thenar compartment muscles and the 2 lumbricals on the radial side
Interosseous muscles are dorsal and palmar muscles. How many on the palmar side? How many on the dorsal side? Where do they originate? Where do they insert?
3 palmar; 4 dorsal; they originate from the metacarpals; insert on the extensor hoods
What do the interosseous muscles do? What are they innervated by?
DAB the PAD. Dorsal interossei ABduct. Palmar interossei ADduct. They are all innervated by the ulnar nerve.
The interossei pass (blank) to the MP axis, so they help flex at the MP joint. They extend at PIP and DIP because they pull on the (blank)
anterior; extensor hood
Interossei and lumbricals pass (blank) to the MP axis, so any pull at this joint causes flexion. As you pull on the extensor hood, this causes extension at the PIP and the DIP, because lateral and central bands pass (blank) to transverse axis.
anterior; dorsal (posterior
What would happen if you pull away the central band of the extensor tendon?
The lateral band will change position and move anterior to the axis. This will cause extension at the DIP or flexion at the PIP
(blank) come off of deep tendons, while the (blank) are closer to the bones.
lumbricals; interossei
This artery courses dorsally through the snuffbox and gives off branches that communicate with ulnar artery through the deep arch of the palm
radial artery
Which arch supplies the most significant flow to the anterior hand?
the superficial arch
T/F: Collateral flow to the hand is NOT the same in everyone. Use Allen test to check for dominant supply.
True
Lumbrical and interosseous muscles insert into the (blank)
extensor hood
What muscle flexes the DIP?
flexor digitorum profundus
What muscle flexes the PIP?
flexor digitorum superficialis
What is the most common wrist fracture in children? What portion of this bone undergoes necrosis when there is non-union due to poor blood supply?
fracture of scaphoid; proximal portion can undergo necrosis
What is the lateral antebrachial cutaneous a branch of? What nerve roots contribute to it?
musculocutaneous nerve; c5, c6, c7
Is the posterior forearm innervated by the superficial branch of the radial nerve?
no; this only supplies cutaneous innervation to the hand.
What is the anterior arm innervated by? What muscles does this nerve specifically supply?
musculocutaneous; biceps brachii, brachialis, coricobrachialis
What innervates the anterior forearm?
the median nerve goes to everything except the flexor carpi ulnaris and 2 digits of the flexor digitorum profundus (ulnar)
What innervates the anterior hand??
all ulnar nerve, except for thenar compartment muscles and 2 lumbricals on functional midline on the radial side (median)
What innervates the shoulder?
axillary nerve (to deltoid and teres minor)
What innervates the posterior arm and forearm?
radial nerve
All the intrinsic muscles of the hand are
innervated by the ulnar nerve except which two? What are these exceptions innervated by?
the thenar compartment muscles (three) and the lumbricals to the functional midline on the radial side (median)
How does damage to the brachial plexus generally present?
as muscle atrophy