9-3a. 1&2 muscular layers - Conference Flashcards
which dermatome is on the lateral aspect of the plantar foot?
S1 dermatome
which nerves serve the S1 dermatome, on the lateral aspect of the plantar foot?
- lateral calcaneal & lateral dorsal cutaneous nerves (from sural nerve) - proximally
- lateral plantar nerve - distally
what nerve innervates the plantar heel area?
medial calcaneal branches
(from tibial nerve)
which nerve innervates the distal aspect of the medial plantar foot/ toes 1-3 and 1/2 of 4?
medial plantar nerve
(from tibial nerve)
which part of the plantar foot is innervated by the saphenous nerve?
middle of the medial plantar foot,
medial to the medial plantar nerve
if glass penetrates the lateral aspect of the plantar foot, which structures are immediately at risk?
- Abductor digiti minimi
- Lateral plantar fascia/ aponeurosis (calcaneal ligament)
what are the 3 muscles of the 1st layer?
2 ABductors, 1 Flexor
- ABductor digiti minimi
- Flexor digitorum brevis
- ABductor hallucis
What is the innervation of the 3 muscles in the 1st layer? (medial –> lateral)
- ABductor hallucis
- Flexor digitorum brevis
- ABductor digitorum brevis
•Medial 2 are innervated by the medial plantar nerve
- ABductor hallucis
- *Flexor digitorum brevis
•Lateral 2* are innervated by the lateral plantar nerve
- *Flexor digitorum brevis
- ABductor digiti minimi
which muscle of the 1st layer can be dually innervated?
which is it not always innervated by?
Though flexor digitorum brevis (FDB) can be dually innervated by the:
- medial plantar nerve
- lateral plantar nerve
* FDB may not always innervated by the lateral plantar nerve
Review the 1st layer muscle origins:
ABdm
FDB
ABh
summary of the 1st layer muscle origins:
3 key points
- medial process and plantar aponeurosis are origin sites for all 3
- lateral process is the only origin for Abductor digiti minimi
- BOTH septa serve as an origin for Flexor digitorum brevis
fibers of the Abductor digiti minimi/quinti that insert onto the MT5 base and shaft form which muscle?
ABductor ossis metatarsi digiti minimi
ABductor digiti minimi/ quinti:
origin
insertion
actions
- origin:
- lateral & medial processes of calcaneal tuberosity
- lateral portion of plantar aponeurosis
- lateral intermuscular septum
- insertion:
- MTPJ capsule
- Extensor expansion
- MT5 head and PP5 base (as does FDMB)
- actions:
- ABducts 5th digit
- Plantarflexes MTPJ 5
FLEXOR DIGITORUM BREVIS
origins
insertions
actions
- origins:
- medial process of calcaneal tuberosity
- central portion of plantar aponeurosis
- medial & lateral intermuscular septa
- insertion:
- both sides of the middle phalanges (2-5)
- actions:
- plantarflexes MTPJs 2-5
- plantarflexes proximal IPJs 2-5
ABDUCTOR HALLUCIS
origin
insertion
actions
- origin:
- Medial process of calcaneal tuberosity
- Medial portion of plantar aponeurosis
- Medial intermuscular septum
- Flexor retinaculum
- insertion:
- MTPJ capsule
- plantar metatarsophalangeal ligament
- extensor expansion
- medial sesamoid
- MT 1 head, and base of HPP
- action:
- ABducts hallux
- plantarflexes hallux at MTPJ
review the relationship of the FHL and the FDL tendons
The flexor digitorum longus tendon crosses over the FHL tendon
LUMBRICALS:
origin
insertion
- origin:
- Flexor digitorum longus (FDL) tendons
- insertion:
- Each lumbrical passes superficially/plantarly to the deep transverse MT ligament
- Inserts onto the medial side of the respective extensor hood/wing (2-5th digits)
LUMBRICALS:
innervation
major actions
- inn:
- 1st = 1st common digital branch of medial plantar n.
- 2nd-4th = deep branch/division of lateral plantar n.
- actions:
- Simultaneously plantarflexes the MTPJ and dorsiflexes the IPJs of the lateral digits.
side the specimen
LEFT SIDE
2 tendinous slips come from the quadratus plantae, and head toward what?
head towards the flexor digitorum longus’ digital slips
