ACSM-EP Musculoskeletal Anatomy 5 — Questions and Answers
Question 1: A client presents with winging of the scapula. Which nerve and muscle are most likely involved?
- Axillary nerve and deltoid
- Long thoracic nerve and serratus anterior (Correct answer)
- Dorsal scapular nerve and rhomboids
- Suprascapular nerve and supraspinatus
Correct answer: Long thoracic nerve and serratus anterior
Scapular winging is classically caused by weakness or paralysis of the serratus anterior due to long thoracic nerve damage, allowing the medial scapular border to lift off the thorax.
Question 2: Which bone forms the posterior portion of the hard palate and also contributes to the floor of the orbit?
- Maxilla
- Zygomatic bone
- Palatine bone (Correct answer)
- Sphenoid bone
Correct answer: Palatine bone
The palatine bone contributes to the posterior hard palate and also forms part of the orbital floor, nasal cavity, and pterygopalatine fossa.
Question 3: During gait, the gluteus medius fires eccentrically during which phase to prevent contralateral pelvic drop?
- Terminal swing
- Initial contact
- Mid-stance on the weight-bearing limb (Correct answer)
- Pre-swing
Correct answer: Mid-stance on the weight-bearing limb
During mid-stance, the gluteus medius of the weight-bearing limb contracts eccentrically to stabilize the pelvis and prevent the swing-side hip from dropping (Trendelenburg sign).
Question 4: The pes anserinus is a conjoined tendon inserting on the medial tibia. Which three muscles form it?
- Sartorius, gracilis, and semitendinosus (Correct answer)
- Biceps femoris, semimembranosus, and gracilis
- Rectus femoris, vastus medialis, and sartorius
- Adductor magnus, semimembranosus, and semitendinosus
Correct answer: Sartorius, gracilis, and semitendinosus
The pes anserinus ('goose foot') is formed by the sartorius, gracilis, and semitendinosus tendons converging on the medial proximal tibia.
Question 5: Which property of bone tissue allows it to resist tensile forces better than compressive forces?
- High mineral content of hydroxyapatite
- Collagen fiber orientation in cortical bone (Correct answer)
- Trabecular bone architecture
- Periosteal thickness
Correct answer: Collagen fiber orientation in cortical bone
The orientation of collagen fibers in cortical bone, aligned along lines of stress, allows bone to resist tensile forces effectively while the mineral phase resists compression.
Question 6: Which cervical vertebra is called the 'axis' and contains the odontoid process (dens)?
- C1
- C2 (Correct answer)
- C3
- C4
Correct answer: C2
C2 is called the axis and has a unique superior projection called the dens (odontoid process) around which C1 (atlas) rotates to allow head rotation.
Question 7: The plantar fascia originates on the calcaneal tuberosity and primarily supports which structure during weight-bearing?
- Lateral longitudinal arch
- Transverse arch
- Medial longitudinal arch (Correct answer)
- Subtalar joint
Correct answer: Medial longitudinal arch
The plantar fascia acts as a tension band that supports the medial longitudinal arch, becoming taut during toe extension via the windlass mechanism.
ACSM-EP Musculoskeletal Anatomy 5
A client presents with winging of the scapula.
Which nerve and muscle are most likely involved?