Lower Extremity Anatomy for NBPME Exam Part I

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Questions and Answers

What condition is associated with inflammation at the attachment of the central portion of the plantar aponeurosis?

Metatarsalgia

Heel spur syndrome

Achilles tendinitis

Plantar fasciitis (correct)

Which structure is NOT formed by the deep fascia or plantar aponeurosis?

Intermuscular septa

Achilles tendon sheath (correct)

Central portion of the plantar aponeurosis

Flexor sheaths

What effect does dorsiflexion of the digits have on the plantar aponeurosis?

Increases tension and heightens the longitudinal arch (correct)

Decreases tension in the aponeurosis

Stimulates blood flow to the toes

Enhances the stability of the ankle

Where is the apex of the central portion of the plantar aponeurosis attached?

Medial process of the calcaneal tuberosity Signup and view all the answers

Which of the following structures forms part of the flexor sheaths in the digits?

Tendons of FHL, FDL, and FDB Signup and view all the answers

What bones are included in the tarsal group of the foot?

Calcaneus, talus, cuboid, navicular, and three cuneiforms Signup and view all the answers

Which division of the foot includes the metatarsals and phalanges?

Forefoot Signup and view all the answers

Which joints separate the different units of the foot?

Midtarsal joint and Lisfranc's joint Signup and view all the answers

Which statement about the talus is correct?

It is the second largest tarsal bone. Signup and view all the answers

What describes the biomechanical division of the foot?

It divides the foot into medial and lateral portions. Signup and view all the answers

What is the total number of phalanges in the foot?

Fourteen Signup and view all the answers

Which bones are located in the lateral portion of the foot?

Calcaneus, cuboid, and fourth and fifth metatarsals Signup and view all the answers

What is the primary function of the sesamoids in the foot?

They reduce friction in the tendons. Signup and view all the answers

What condition is characterized by inflammation of the attachment of the central portion of the plantar aponeurosis to the medial process of the calcaneal tuberosity?

Plantar fasciitis Signup and view all the answers

Which structure is located at the anterosuperior aspect of the medial surface of the calcaneus?

Sustentaculum tali Signup and view all the answers

Which surface of the calcaneus is noted to be smooth for a bursa for the tendo calcaneus?

Posterior surface Signup and view all the answers

What is the shape of the articular surface between the calcaneus and cuboid?

Saddle-shaped Signup and view all the answers

The peroneal tubercle is located relative to which structure on the lateral surface of the calcaneus?

Anterior to the retrotrochlear eminence Signup and view all the answers

How many surfaces does the cuboid bone have?

Six Signup and view all the answers

Which of the following tendons runs along the inferior aspect of the sustentaculum tali?

Tendon of flexor hallucis longus Signup and view all the answers

What type of joint forms between the cuboid and the fourth and fifth metatarsals?

Tarsometatarsal joint Signup and view all the answers

Which structure does NOT form part of the fibula's distal extremity?

Malleolar fossa Signup and view all the answers

What is the primary characteristic of the patella's posterior surface?

It has a rough area for ligament attachment. Signup and view all the answers

Which feature distinguishes the lateral facet of the patella?

It is larger and has less of a slope than the medial facet. Signup and view all the answers

What is the anatomical role of the trochlea of the femur?

Contributes to weight transmission in the knee joint. Signup and view all the answers

Which of the following statements about the femur is incorrect?

It is the shortest bone in the human body. Signup and view all the answers

How is the architecture of the femur primarily described?

It has a typical long bone structure. Signup and view all the answers

What feature of the fibula’s distal extremity sets it apart from the medial malleolus?

It projects further inferiorly. Signup and view all the answers

What is a common anatomical issue associated with the patella?

It often dislocates laterally. Signup and view all the answers

What features are connected anteriorly by the patellar surface on the femur?

The medial and lateral condyles Signup and view all the answers

How does the medial condyle of the femur compare to the lateral condyle?

It extends further inferiorly. Signup and view all the answers

Which part of the os coxae is formed by the union of the ilium, ischium, and pubis?

Acetabulum Signup and view all the answers

What does the ilium form in the os coxae?

Superior portion of the os coxae Signup and view all the answers

Which surface is part of the gluteal surface of the ilium?

Anterior gluteal line Signup and view all the answers

What characterizes the axis of the functional subtalar joint?

It is fixed and allows triplanar motion. Signup and view all the answers

Which clinical note relates to the iliac crest?

It serves as a landmark for limb length measurements. Signup and view all the answers

During open kinetic chain (OKC) pronation, which movements occur simultaneously?

Eversion, abduction, and dorsiflexion. Signup and view all the answers

What structure marks the beginning of the greater sciatic notch?

Posterior superior iliac spine Signup and view all the answers

What prevents the abduction/adduction movements in closed kinetic chain (CKC) motion?

Friction and ground reactive forces. Signup and view all the answers

What separates the medial and lateral condyles of the femur posteriorly?

Intercondylar fossa Signup and view all the answers

What does CKC supination include?

Calcaneal inversion and abduction of the talus. Signup and view all the answers

What is a motion characteristic of CKC pronation?

Calcaneal eversion with internal rotation. Signup and view all the answers

Which statement accurately describes the talus in the CKC motion?

It maintains transverse and sagittal plane motion. Signup and view all the answers

What type of motion does the functional subtalar joint allow?

Triplanar motion including supination and pronation. Signup and view all the answers

What is the angulation of the subtalar axis from the transverse plane?

42 degrees. Signup and view all the answers

Study Notes

Lower Extremity Anatomy for NBPME Part I Exam

This document is a study guide for an anatomy exam covering the lower extremity.
Dr. Daniel Bareither is the author.

Part 1 - Osteology (Bony Landmarks and Associated Structures and Ossification)

Question areas: Foot, Leg, Thigh, and Gluteal region.

Bones of the Foot

Anatomical position: Foot is at a right angle to the leg.
Divisions of the foot: Tarsus, Metatarsus, Phalanges, and Sesamoids.
Tarsus: Calcaneus, talus, cuboid, navicular, and three cuneiforms.
Metatarsus: Five metatarsal bones.
Phalanges: Fourteen bones forming the toes.
Sesamoids: Two bones within the tendons of flexor hallucis brevis.
Biomechanical division of the foot: Medial and lateral columns.
- Medial column: Calcaneus, talus, navicular, three cuneiforms, first, second, and third metatarsals with their respective phalanges, and the constant sesamoids.
- Lateral column: Calcaneus, cuboid, and fourth and fifth metatarsals with their respective phalanges.
Surgical division (forefoot, midfoot, and rearfoot).
- Forefoot: Metatarsals (five), phalanges (fourteen), sesamoids (two).
- Midfoot: Navicular, cuboid, and three cuneiforms.
- Rearfoot: Calcaneus and talus.
- Anatomical note: Midtarsal joint (transverse tarsal or Chopart's joint) joins the rearfoot and the midfoot, while Lisfranc's joint(tarsometatarsal joint) connects the midfoot and the forefoot.

Talus

Second largest tarsal bone.
Located superior and posterior aspect of the foot.
Does not have any muscular attachments.
Articulates with: tibia and fibula (ankle joint), calcaneus (subtalar joint), navicular (talonavicular portion of midtarsal joint).
Composed of: Body, Neck, and Head.
- Body: Cuboid in shape, located posteriorly, has five surfaces (superior, inferior, medial, lateral, and posterior).
- Neck: Constricted and directed anteriorly and medially from the body. Has numerous nutrient foramina for vascular supply.
- Head: Articular surface for the navicular, three facets on inferior surface (middle calcaneal, anterior calcaneal, and facet for spring ligament).
- Superior surface: Trochlea, articular surface for the distal extremity of the tibia, Wider anteriorly than posteriorly.
- Inferior surface: Posterior calcaneal articular surface for the posterior articular facet on the superior surface of the calcaneus.
- Medial surface: Articular facet for the medial malleolus.
- Lateral surface: Articular facet for the lateral malleolus, Roughened apex of lateral process.
Posterior surface: Posterior process, Medial and lateral tubercle, Groove for flexor hallucis longus tendon.

Calcaneus

Largest bone of the foot, also known as the heel bone.
Projects posteriorly from the ankle joint to create a lever.
Articulates with the talus (subtalar joint), cuboid (calcaneocuboid portion of midtarsal joint).
Six surfaces: posterior, anterior, medial, lateral, superior, and inferior.
Superior surface: Posterior, middle, and anterior facets. Calcaneal sulcus located between the posterior and middle facets.
Inferior surface: Calcaneal tuberosity comprised of medial and lateral tubercle with a groove between. Medial process is larger than the lateral. Tubercle with a transverse groove anterior to it (infracalcaneal exostosis or heel spur).
Other surfaces (superior, medial, lateral): Relevant articular facets.

Cuboid

Pyramidal in shape.
Articulates with calcaneus, fourth and fifth metatarsals (tarsal and Lisfranc's joint).
Six surfaces (posterior, anterior, medial, lateral, superior, and inferior).
Superior surface: Peroneal sulcus/groove for peroneus longus at anterior aspect. Peroneal ridge, ends laterally in a tuberosity (beak-like process called the beak of the cuboid, coronoid process of the cuboid).
Other surfaces (superior, medial, lateral): Relevant articular surfaces.

Navicular (Scaphoid)

Located on the medial side of the foot.
Articulates with the talus (talonavicular portion of midtarsal joint), three cuneiforms (cuneonavicular joints), occasionally with the cuboid (cuboideonavicular joint), and the calcaneus (calcaneonavicular joint).
Six surfaces (posterior, anterior, medial, lateral, superior, and inferior).
Superior surface: Groove for tibialis posterior tendon.
Medial surface: Tuberosity for tibialis posterior.
Lateral surface: Occasional facet for articulation with the cuboid.
Anterior surface: Articular surface divided into three facets for articulation with the three cuneiforms.
Posterior surface: Articular surface for the head of the talus.

Cuneiforms

Triangular (wedge-shaped) in morphology.
Three in number (medial, intermediate, lateral).
Articulations with each other and other relevant bones.

Metatarsals (1-5)

Miniature long bones with a base, shaft, and head.
Numbered 1 to 5 from medial to lateral.
Distal projection (in the articulated foot): 2>3>1>4>5 (major variation is 2>1>3>4>5)
Shaft: Tapers from base to head, articular with tarsus, & lesser metatarsals (articulating with each other), and five surfaces (posterior, medial, lateral, superior, and inferior).
Proximal extremity: Heads of lesser metatarsals, articulate with the proximal phalanx.
Common characteristics of the head and base.
- Heads - Concave plantarly, lateral and medial extensions; plantar condyles.
- Base - Articulate with the tarsus, and lesser metatarsals with each other.

First Metatarsal

Shortest but strongest .
Articulates with first cuneiform (tarsometatarsal joint), proximal phalanx of hallux (metatarsophalangeal joint), medial and lateral sesamoids (metatarsophalangeal joint), and second metatarsal base (intermetatarsal joint).
Base, Shaft, and Head.
Significant clinical considerations.

Second Metatarsal

Longest.
Articulates with second cuneiform (tarsometatarsal joint), proximal phalanx (metatarsophalangeal joint), first cuneiform (tarsometatarsal joint), third cuneiform (tarsometatarsal joint), third metatarsal base (intertarsal joint), and first metatarsal base (intertarsal joint).
- Base - Triangular, medial surface: oval facet for first cuneiform, lateral: two facets for third metatarsal.
- Shaft - Same as common characteristics.
- Head - Same as common characteristics.

Third Metatarsal

Intermediate size.
Articulates with third cuneiform (tarsometatarsal joint), proximal phalanx (metatarsophalangeal joint), second metatarsal base (intertarsal joint), fourth metatarsal base (intertarsal joint), and cuboid (cuneocuboid joint).
- Base - Triangular, medial surface: two facets for second cuneiform, lateral: facet for fourth.
- Shaft - Same as common characteristics.
- Head - Same as common characteristics.

Fourth Metatarsal

Articulates with cuboid (tarsometatarsal joint), proximal phalanx (metatarsophalangeal joint), third cuneiform (tarsometatarsal joint), third metatarsal base (intermetatarsal joint), and fifth metatarsal base (intermetatarsal joint).
- Base - Posterior surface: Quadrate, medial: facet for third, lateral: facet for fifth.
- Shaft - Same as common characteristics.
- Head - Same as common characteristics.

Fifth Metatarsal

Articulates with cuboid (tarsometatarsal joint), proximal phalanx (metatarsophalangeal joint), fourth metatarsal base, (intermetatarsal joint).
- Base - Posterior surface: triangular, medial: facet for fourth, lateral: large and prominent.
- Shaft - Same as common characteristics.
- Head - Same as common characteristics.

Phalanges

Bones that make up the toes.
The first toe (hallux) has 2 phalanges, other toes have 3.
Consist of: Base, shaft, and head.
Proximal, middle, and distal phalanges for each toe.

Constant Sesamoids

Medial or tibial sesamoid
Lateral or fibular sesamoid
Embedded in flexor hallucis brevis tendons and plantar plate.
Articulate with the inferior surface of the first metatarsal head.

Ossification of Bones

Ossification times are average values from various studies.
Females usually ossify faster than males.
Not uncommon for one foot to develop slightly differently than the other.
Primary centers typically begin in fetal development, although some appear after birth
Secondary centers also occur during fetal development but most finalize after birth.

Accessory Bones

Accessory bones are not part of the normal osteology but are sometimes present in a small percentage of the population.
The two types of accessory bones are: -Ossicles resulting from anomalous development or ossification -Sesamoids found in tendons and joint capsules to decrease friction.
Common locations for accessory ossicles on the dorsum: -Os trigonum (talus secondarius) -Os tibiale externum -Os intermetatarseum -Os supranaviculare
Less common locations for ossicles: -Os paracuneiform
- Os supranaviculare or talonavicular dorsalis, or calcaneonavicular (dorsal)
- Os subtibiale
- Os subfibulare

Part 2 - Arthrology (Joint Classification, Articular Facets, Ligamentous Support, Movements)

Question areas: Ankle, foot, knee, tibiofibular, pelvis, and hip

Ankle Joint

Synovial joint formed by the malleolar fork (medial and lateral malleoli of tibia and fibula) and the talar dome.
Superficial and deep deltoid (medial) ligaments and lateral (anterior talofibular) and (calcaneofibular) ligaments.

Joints of the Foot

Intertarsal (synovial): Gliding, rotational.
Functional subtalar (talocalcaneal): Single axis for triplanar motion, allows supination and pronation. -Open kinetic chain (OKC) and Closed kinetic (CKC) aspects of movement.
Functional midtarsal (transverse tarsal or Chopart's): Calcaneocuboid and talonavicular. Allows simultaneous inversion/eversion and pronation/supination.
Tarsometatarsal (Lisfranc's): Connects the cuneiforms and cuboid with the metatarsal bases. Provides more mobility at the 1st and 5th tarsometatarsal joints.
Intermetatarsal: Lesser metatarsal bases articulate with each other.
Lesser metatarsophalangeal (MPJ): Synovial, biaxial joints where the metatarsals articulate with the proximal phalanges of toes 2-5.
Hallux metatarsophalangeal (MPJ): Synovial, permits dorsiflexion/plantarflexion movements around a transverse axis, and abduction/adduction around a vertical axis.
Interphalangeal (IPJ) joints (proximal and distal): Synovial, facilitate only dorsiflexion and plantarflexion.

Knee Joint

Synovial, biaxial, hinge-type joint between the distal end of the femur and the proximal tibia, and the patella.
- Synovial membrane: Projects around the cruciate ligaments so that the they are extrasynovial, but superiorly the synovial cavity connects with the suprapatellar bursa.
- Ligaments:
- Collateral ligaments (medial and lateral)
- Cruciate ligaments (anterior and posterior)
Menisci: crescent-shaped fibrocartilages embedded in the joint, distribute force across the tibial plateau.

Hip Joint

Ball-and-socket synovial joint combining the head of the femur with the acetabulum of the os coxae.
Synovial articulation, with a fibrocartilaginous acetabular labrum to deepen the cavity and an articular capsule.
Ligaments: Iliofemoral, Ischiofemoral, Pubofemoral ; Ligamentum capitis femoris

Sacroiliac Joint

Synovial joint between the paired auricular surfaces of the sacrum and ilium, allowing for limited movement, chiefly to accommodate the changes in posture and position throughout life.
Ligaments: Anterior, Posterior, Interosseous sacroiliac.

Miscellaneous Ligaments of the Thigh

Inguinal, Lacunar, Pectineal, Obturator membrane.

Part 3 – Myology (Muscle Origins, Insertions, Actions; Fascia and Retinacula)

Question areas: Foot, Leg, Thigh, and Pelvis

Dorsum of the Foot

Skin
Deep fascia
Superior extensor retinaculum
Inferior extensor retinaculum
Flexor retinaculum
Extensor digitorum brevis: Origin, Insertion, Action
Tendons of extrinsic muscles
Extensor hood or extensor expansion

Plantar Surface of the Foot

Skin
Deep fascia
First layer of plantar muscles
Second layer of plantar muscles
Third and fourth layers of plantar muscles
Tendons of extrinsic muscles

Muscular Compartments of the Foot

Muscles of the Leg

Anterior compartment of leg muscles

Tibialis anterior, Extensor hallucis longus, Extensor digitorum longus, Peroneus tertius.

Lateral compartment of leg muscles

Peroneus longus, Peroneus brevis

Posterior compartment of leg muscles

Superficial group: Gastrocnemius, Soleus, Plantaris
Deep group: Popliteus, Flexor digitorum longus, Tibialis posterior, Flexor hallucis longus

Popliteal Fossa

Part 4 - Angiology (Arteries, Veins, and Lymphatics)

Question areas: Foot, Leg, Thigh, and Pelvis

Superficial Veins of the Foot and Leg

Great saphenous and Small saphenous.

Arteries of the Foot and Leg

Dorsalis pedis and Plantar
Medial, Lateral, Perforating
Collateral, Cruciate anastomoses arteries of the knee and hip.

Part 5 – Peripheral Nervous System (Lumbar and Sacral Plexuses, Their Cutaneous, Articular, Somatic, Motor and Sympathetic Branched of the Lower Extremity)

Question Areas: Foot, Leg, Thigh, Hip, and Pelvis • Cutaneous innervation of the lower extremity • Muscular innervation of the lower extremity
Lumbosacral Plexus (Lumbar and Sacral Portions)
Lumbar portion: Iliohypogastric, Ilioinguinal, Genitofemoral, Lateral femoral cutaneous nerve, Obturator nerve, Femoral nerve
Sacral portion: Nerve to quadratus, nerve to obturator internus, nerve to piriformis, Superior gluteal nerve, Inferior gluteal nerve, Posterior femoral cutaneous nerve, Sciatic nerve, Tibial nerve, Common peroneal nerve, Pudendal nerve.

Part 6 - Integument

Composition
Thick skin
Thin skin
Hypodermis

Part 7 - Limb Development (Limb Bud and Limb Rotation; Pre-axial Versus Post-axial Position and Function)

Limb Bud Formation
Limb Bud Structure
Limb Bud Coordinates
Mesoderm of Limb Bud
Limb Differentiation
Limb Rotation

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This quiz serves as a study guide specifically for the anatomy of the lower extremity, focusing on osteology. Key areas covered include the bones of the foot, leg, thigh, and gluteal region. Ideal for students preparing for the NBPME Part I exam.