Head, Neck and Trunk Flashcards
Head and Neck Muscles’ Motion
Head and neck muscles allow for motion in all three planes. Motions are: • Flexion (sagittal) • Extension (sagittal) • Lateral Flexion (frontal) • Rotation (transverse)
Bones of the Neck
- 7 Cervical Vertebrae (C1–T1)
- C1 = Atlas
- C2 = Axis
Atlas vs. Axis
Two top-most vertebrae of neck. C1 and C2. Different from other vertebrae as they have no body and no disk between.
ATLAS: C1; articulates with occipital process of skull for flexion/extension (“YES”)
AXIS: C2; articulates with Atlas for rotation motion (“NO”)
Cervical Vertebrae
C1-C7
• Bear less weight than thoracic/lumbar
• More mobile; ½ of cervical rotation occurs at C1-C2
• C1 has extra space for spinal cord
• Body (wider, interior flat bone area) smaller than lower vertebrae
Vertebral Design
All vertebrae have similar structural design, but regional variation in size/configuration.
• Increase in size from Cervical to Lumbar, then decrease in size from Sacral to Coccygeal
• TRABECULAR SYSTEM: made of system of vertical, horizontal and oblique fibers that correspond to stress placed on body; pattern determines “hardness” of that area of vertebra
Intervertebral Disks
Round, fibrous gel-like disks located between the vertebrae (all but C1-C2).
• Shock absorbers and increase flexibility/mobility of spine
• ~25% of vertebral column height
• 3-9mm thick
• 2 parts: Nucleus Pulposus (gel center) and Annulus Fibrosis (outer fibers)
• Wedge-shaped to contribute to spinal curves in cervical and thoracic regions
• Nutrition occurs through osmosis, not directly (poor blood supply/slow healing)
• Herniation occurs when compressed (HNP=herniated nucleus pulposus)
• Degeneration begins ~age 20; gradual loss of water in nucleus; progressive fibrosis (hardening)
Number of muscles in head and face
Over 50 muscles are in the head and face. They are more than 1/5 of total muscles in body.
Brachial Plexus
Nerves C5 to T1; nerves for arms
• Provides neuromuscular protection and redundancy (if one nerve is damaged, another might take its place)
• Peripheral nerves of UE originate from brachial plexus
• System of trunks, divisions and cords which terminate in individual nerves (terminal branches)
• Originates in ventral rami of lower cervical spine (C5-T1)
• Mixed nerves that carry both sensory/motor
Ramus vs. Trunk
In Brachial Plexus, RAMUS is where nerve exits the spinal cord, and multiple rami come together to form 3 TRUNKS:
• Superior (C5 and C6)
• Middle (C7)
• Inferior (C8 and T2)
Trunk vs. Division
In Brachial Plexus, TRUNK is where rami come together. Trunk then branches into 3 DIVISIONS:
• Anterior (middle and superior trunks)
• Posterior (superior, middle and inferior)
• Inferior (inferior trunk)
Division vs. Cord vs. Terminal Branch
In Brachial Plexus, the DIVISIONS end in 3 different CORDS, which provide pathways for the terminal branches laterally, posteriorly and medially along arm. TERMINAL BRANCHES:
• Posterior Cord (branches to thoracodorsal, radial, axillary, subscapular)
• Lateral Cord (to lateral pectoral, musculocutaneous)
• Medial Cord (to medial pectoral, ulnar)
** Lateral cord joins with medial cord to form median nerve
Brachial Plexus Injuries
- Can have brachial plex injuries and be otherwise healthy.
- Only affects one arm (not like spinal cord injury SCI)
- Unless disabled by pain, remain active and can carry out ADLs one-handed
- May prefer to use sound limb and remain one-handed
- May lose sensory feedback from skin, muscles and joints; may need to be aware of insensate skin!
Muscle Contracture
When nerve injury causes muscle to get “stuck.” Ex: if wrist extensors are gone, you can flex but can’t go back (stays flexed).
Neurologic Impairment with loss of C5-6 (top of brachial plexus)
- Motor Deficit: shoulder abd and flexion; elbow flexion; wrist extension
- Sensory Loss: lateral arm, forearm, thumb/index fingers
- Functional Need: support shoulder; prevent subluxation; flex elbow
Order of nerve breakdown in brachial plexus (proximal to distal)
Ramus > Trunk > Division > Cord > Terminal Branch
Neurologic Impairment with loss of C6-7 (mid brachial plexus)
- Motor Deficit: shoulder abd and flexion; elbow flexion; wrist extension (same as C5), but also add elbow/wrist/finger extension weakness
- Sensory Loss: lateral arm, forearm, thumb/index fingers (same as C5), but also add middle finger
- Functional Need: support shoulder; prevent subluxation; flex elbow (same as C5), but also add support for wrist/finger/thumb extension
Neurologic Impairment with loss of C8-T1 (lower brachial plexus)
- Motor Deficit: Wrist/finger/thumb flexors; finger/thumb extensors
- Sensory Loss: Little/ring fingers; medial forearm
- Functional Need: Wrist stabilization; finger flex/extend; intrinsic function
Neurologic Impairment with loss of C5-T1 (all of brachial plexus)
- Motor Deficit: “flail arm”; no muscle control (+/- scapula)
- Sensory Loss: total forearm; lateral arm; entire hand
- Functional Need: Support and protect limb (wear a sling)
ROM for Head and Neck
• Difficult to measure, as there are few bony landmarks and soft tissue overlying. Normal ROMs: • Capital Extension: 0-25˚ • Capital Flexion: 0-15˚ • Cervical Extension: 0- <30˚ • Cervical Flexion: 0-45˚ • Capital + Cervical Extension: 0-45˚
**NOTE: OTA domain does not include MMT for head/neck so we don’t need to know this.
Movements of Lower Back
Moves in three planes:
• Flexion/Extension (sagittal)
• Lateral Flexion/Bending and Reduction/Return (frontal)
• Rotation (transverse)
Thoracic Vertebrae
Bones of upper/mid back. T1-T12.
• Each articulates with a pair of ribs
• Less flexible and more stable than cervical
• Rotation-free in upper area, and decreases caudally
Curves of Spine
- Cervical Curve (lordotic)
- Thoracic Curve (kyphotic)
- Lumbar Curve (lordotic)
- Pelvic Curve (kyphotic)
Lumbar Vertebrae
Largest vertebrae of lower back.
• Holds the most weight above
• L5 is a transitional segment; body is wedge-shaped to connect with sacrum
• L5 creates biggest curve/can cause spondylosis if out of place
• L4-L5 are usually where injury occurs
Sacrum
Five fused vertebrae below lumbar spine.
• Sacroiliac Joints: support HAT (head, arms, trunk); smooth motion in all directions in childhood, decreased motion later as surfaces change. Supported by 4 groups of ligaments.
ROM of Trunk
- Thoracic Spine Extension: 0˚
- Lumbar Spine Extension: 0˚ to 25˚
- Trunk Flexion: 0˚ to 80˚
- Trunk Rotation: 0˚ to 45˚
Pelvic Girdle
• Joins lower skeleton to upper body via the lumbrosacral joint.
• Movements include:
- Anterior tilt (ASIS anterior to pubic symphysis/inferior to PSIS; swayback)
- Posterior tilt (ASIS posterior to pubic symphysis/superior to PSIS; butt tuck)
- Lateral tilt (Iliac crest moves superior/inferior relative to contralateral side; one side rises)
ASIS vs. PSIS
ASIS = anterior superior iliac spine (top front points of pelvis)
PSIS = posterior superior iliac spine (top back points of pelvis)
HAT
Head, Arms, Trunk
Neutral Pelvic Tilt when Seated
- Pelvis midway between anterior/posterior tilt
- Equal weight on both femurs
- Erect spine/normal lordosis
- Head aligned over hips
Anterior Pelvic Tilt
When pelvis dips/tilts forward, lifting the buttocks upward.
Muscle(s) causing hip flexion
Iliopsoas group: Psoas Major and Iliacus
Posture of elderly individuals
Postures become similar to a child: wide base of support, flexed knees and hips, flattened lumbar spine, and increased thoracic kyphosis.
Number of cervical vertebra and cervical nerves:
7 Cervical Vertebra
8 Cervical Nerves (one above the Atlas)
Main Nerves of the Brachial Plexus
5 Terminal BRANCHES (5 Main Nerves):
1) Musculocutaneous Nerve (C5, C6, C7)- Elbow flexors
2) Axillary Nerve (C5, C6) – Teres minor and Delts (Shoulder)
3) Radial Nerve (C5-T1) – Extensors: Triceps, extrinsic wrist/hand extensors
4) Median Nerve (C6-T1) – Forearm, thenar, lateral lumbricals
5) Ulnar Nerve (C8, T1) – Hand except thenar and lateral lumbricals
