BMS101 - MUSCLES

What is a circular muscle and give an example

Fibres arranged in a circle around an opening; constrict openings. Example: Orbicularis oris

What is a parallel muscle and give an example

Fibres run parallel to the long axis; allow efficient shortening. Example: Rectus abdominis

What is a convergent muscle and give an example

Fibres converge from a broad origin to a single insertion; versatile movement. Example: Pectoralis major

What is a unipennate muscle and give an example

Fibres attach obliquely to one side of a tendon; increases force. Example: Extensor digitorum

What is a bipennate muscle and give an example

Fibres attach obliquely to both sides of a tendon; more force than unipennate. Example: Rectus femoris

What is a multipennate muscle and give an example

Fibres attach to multiple branches of a tendon; maximises force in multiple directions. Example: Deltoid

A muscle has fibres coming off one side of a central tendon. What type is it?

Unipennate

Why is the deltoid muscle classified as multipennate?

It has three tendon branches with fibres running obliquely between them

Break down sternocleidomastoid and its attachments

Sterno = sternum

How many heads do the biceps brachii and triceps brachii have?

Biceps brachii = 2 heads; Triceps brachii = 3 heads

Meaning of Maximus

Largest

Meaning of Medius

Medium size

Meaning of Minimus

Smallest

Meaning of Rectus

Straight fibres

Meaning of Oblique

Fibres at an angle

Meaning of Brachii

Located in the arm

Meaning of Femoris

Located in the thigh/femur

How does rectus femoris indicate shape and location?

Rectus = straight fibres; Femoris = located on the thigh

Major groups of axial muscles and their primary functions

Head & neck (move head)

Muscle responsible for upright posture

Erector spinae

Muscles responsible for facial expression

Orbicularis oris/oculi

Muscles responsible for mastication

Temporalis

Muscles responsible for breathing

Diaphragm

Role of erector spinae

Extends and stabilizes vertebral column; maintains posture

Muscle moving the jaw during chewing and location

Temporalis; located above the ear

Two types of intercostal muscles and actions

External = elevate ribs (inhalation); Internal = depress ribs (forced exhalation)

Role of diaphragm in inhalation and exhalation

Contracts and flattens to inhale; relaxes and domes to exhale

Muscles used to blow out air forcefully

Internal intercostals and abdominal muscles (rectus abdominis

Four abdominal muscles and main functions

Rectus abdominis (trunk flexion)

Difference between pretty abs and functional deep core muscles

Pretty abs = superficial

Abdominal muscles used during torso rotation to the right

Left external oblique + right internal oblique

Difference in fibre direction between external and internal obliques

External = downward/medial; Internal = upward/medial; allows rotation & stability

Major rotator cuff muscles and function

Supraspinatus

Functions of biceps brachii vs triceps brachii

Biceps = elbow flexion & supination; Triceps = elbow extension

How does “brachii” indicate location?

Means the muscle is located in the upper arm

Main function of the deltoid muscle and differences in sections

Shoulder abduction; anterior = flexion

Muscles called quadriceps and main function

Rectus femoris

Hamstring muscles and their roles

Biceps femoris

Biggest gluteal muscle

Gluteus maximus

How does the patella facilitate knee movement?

Increases leverage of quadriceps tendon

Muscles responsible for plantarflexion of the ankle

Superficial: Gastrocnemius

Muscle responsible for dorsiflexion of the ankle

Tibialis anterior

Flexion + example

Decrease joint angle; e.g.

Extension + example

Increase joint angle; e.g.

Abduction + example

Movement away from midline; e.g.

Adduction + example

Movement toward midline; e.g.

Medial rotation + example

Rotates limb toward midline; e.g.

Lateral rotation + example

Rotates limb away from midline; e.g.

Agonist-antagonist pair for elbow flexion and extension

Flexion = biceps brachii (agonist)

Why are multiple muscles needed to move a single joint?

Provides precise control and distributes force; e.g.

During a bicep curl

which muscles are prime mover

Weak transverse abdominis causes what functional problems?

Poor core stability

Why can someone without palmaris longus still grip normally?

Other forearm flexors compensate (flexor carpi radialis/ulnaris)

Patient cannot extend knee. Which muscles are likely compromised?

Quadriceps group (rectus femoris + vastus muscles)

Muscles active during a “good morning” exercise

Erector spinae