Muscle:Splenius Capitis
Splenius capitis is a broad, strap-like neck muscle whose trigger points (TrPs) refer pain sharply to the vertex of the skull on the same side. It is one of the most common muscular sources of unilateral vertex headache, and its TrPs are frequently overlooked in patients labelled with tension headache or occipital neuralgia following whiplash.
Because it lies deep to the trapezius but superficial to the semispinalis capitis, it occupies a surgically important position near the exposed vertebral artery at the C₁ level — a relationship that demands caution during both injection and deep palpation.
Contents
- 1 Anatomy
- 2 Referred Pain Patterns
- 3 Activation and Perpetuating Factors
- 4 Clinical Examination
- 5 Differential Diagnosis
- 6 Treatment
- 7 Satellite Trigger Points
- 8 Related Pages
- 9 References
Anatomy
The splenius capitis attaches below in the midline to the fascia over the spinous processes of the lower half of the cervical spine and over the first three or four thoracic vertebrae. Above and laterally, its fibres attach to the mastoid process and to the adjacent occipital bone, immediately underneath the attachment of the sternocleidomastoid muscle.
Primary actions: Extension of the head and neck bilaterally; ipsilateral rotation of the head and neck when acting unilaterally. The muscle showed strong bilateral activity during extension and unilateral activity during rotation of the face to the same side in fine-wire EMG studies. It is not active at rest in the upright balanced position, and did not become active during lateral flexion.
When the chin is tilted upward, both splenius capitis muscles work vigorously: the ipsilateral muscle rotates the head and neck, while the contralateral muscle helps to extend the head and neck.
Innervation: Lateral branches of the dorsal primary divisions of spinal nerves C₂–C₄, frequently also C₁, sometimes C₅, and rarely C₆.
Main synergists (extension): Semispinalis capitis and cervicis, posterior cervical group as a whole.
Synergists (ipsilateral rotation): Ipsilateral levator scapulae, contralateral upper trapezius, semispinalis cervicis, deep spinal rotator muscles, sternocleidomastoid.
Antagonists (rotation): Contralateral levator scapulae, ipsilateral upper trapezius, semispinalis cervicis, deep spinal rotators, sternocleidomastoid.
Bilaterally, the paired splenius cervicis and splenius capitis muscles each form a "V" shape. The trapezius muscle covers much of both splenii.
Referred Pain Patterns
Vertex Referral
A TrP in the splenius capitis refers pain to the vertex of the head on the same side — a sharply localised, top-of-skull ache that patients often describe by pressing a single finger to the crown of the head. This is the defining, must-have feature that distinguishes splenius capitis involvement from all other cervical muscles.
An unusually craniad location of a splenius capitis TrP, near the level of C₂ (just caudad to the exposed vertebral artery), refers pain to the orbit — an "ache inside the skull." The black dash line and arrow in the classic Figure 15.1A indicate that the pain seems to shoot through the inside of the head to the back of the eye.
Overlapping Patterns
At least seven other head and neck muscles have similar or overlapping pain patterns and must be considered in the differential:
- Semispinalis cervicis
- Suboccipital muscles
- Levator scapulae
- Sternocleidomastoid
- Upper trapezius
- Temporalis
- Deep masseter
Activation and Perpetuating Factors
Postural Factors
Postural stresses that overload extension or rotation of the head and neck are the most common initiating and perpetuating mechanism:
- Working at a desk with the head turned to one side and projected forward to see documents or a display screen
- Bird-watching through binoculars while seated in a position that extends the neck to compensate for a strong thoracic kyphosis
- Assuming a similar posture of head and neck extension while playing certain musical instruments (e.g. accordion)
- Falling asleep with the head and neck bent in a crooked position — such as with the head on the armrest of a sofa without an adequate pillow
Impact and Activity Stress
- Whiplash (acceleration-deceleration injury): The splenius capitis was the second most frequently involved muscle in a systematic study of 100 motor vehicle accident occupants examined for TrPs — present in 94% of frontal impacts, 77% of rear impacts, 75% of broadside impacts on the passenger side, and 69% of broadside impacts on the driver's side.
- Sudden overload — pulling on a rope while rotating or projecting the head forward
- Pulling excessive weight on exercise equipment pulleys, particularly when the head is rotated or projected forward
Environmental Factors
A cold air conditioner or cool draft blowing on the exposed neck, together with muscular fatigue, greatly increases the likelihood of TrP activation. The patient should keep the neck warm, particularly when the muscles are already tired.
Clinical Examination
Range of Motion Assessment
Patient examination reveals:
- Moderate restriction of passive head and neck flexion and rotation to the opposite side
- Painful restriction of active head and neck rotation to the same side
Flexion of the chin onto the chest may lack a distance of one or two finger widths.
Trigger Point Examination
Splenius capitis TrPs are identified by flat palpation and are usually found near the region where the upper border of the upper trapezius crosses the splenius capitis (see Fig. 20.7 in the source volume). Most of the muscle's course lies between and deep to other muscles. The splenius capitis lies superficial to the semispinalis capitis and deep to the trapezius.
Localisation technique:
- Palpate the mastoid process and the prominent sternocleidomastoid muscle (identified by asking the patient to look away from the side being examined and sidebend the head toward that side)
- Place one finger posterior and medial to the sternocleidomastoid, below the occiput
- Palpate contraction of the diagonal splenius capitis fibres by asking the patient to turn the face toward the side being examined and extend the head against light resistance supplied by the operator
This muscle is palpable within the small muscular triangle bounded anteriorly by the sternocleidomastoid, posteriorly by the upper trapezius, and caudad by the levator scapulae. In some patients the splenius may be taut enough to be clearly palpable without active assistance.
Elongation test: Both splenius capitis and splenius cervicis are elongated by neck flexion, but only the splenius capitis is further elongated by flexion of the head on the cervical spine — a useful distinguishing manoeuvre during examination.
Tenderness near the mastoid insertion is more likely to indicate enthesopathy secondary to tension from a mid-muscle TrP, rather than a primary TrP at that location.
Differential Diagnosis
| Condition | Distinguishing features |
|---|---|
| Cervicogenic / tension headache | Splenius capitis TrPs are a primary unrecognised source; confirm by reproducing the vertex pain on TrP palpation |
| Occipital neuralgia | Splenius capitis pain has been previously misdiagnosed as occipital neuralgia; myofascial pain lacks the lancinating neuralgic quality and is reproduced by muscle palpation |
| Whiplash syndrome / hyperextension injury | Splenius capitis is one of the most commonly injured muscles; myofascial TrP component is frequently overlooked in favour of posterior muscle involvement alone; anterior neck and chest muscles (SCM, pectoralis minor) must also be examined |
| Spasmodic torticollis (wry neck) | Neurological condition with paroxysmal or clonic contractions and muscle hypertrophy with fibrotic change; myofascial tautness has steady resistance without paroxysmal contractions; spasmodic torticollis appears to have central nervous system origin |
| Semispinalis cervicis, suboccipital, levator scapulae TrPs | All can produce overlapping occipital and upper cervical pain; vertex localisation on the same side is most characteristic of splenius capitis; differential palpation of taut bands in each muscle required |
| The most common articular dysfunction associated with splenius capitis TrP is a C₂ dysfunction; with TrPs in the splenii, multiple and varied cervical articular dysfunctions are frequently found |
Treatment
Trigger Point Release
The splenius capitis and splenius cervicis are generally released together with their synergists as part of one treatment unit. Tightness in one muscle may prevent full stretch of the parallel synergistic units.
Spray and stretch technique:
- Patient seated with shoulder girdle horizontal (pelvis levelled if necessary)
- Head rotated 20–30° away from the involved splenii, and gently flexed toward the opposite side
- Vapocoolant spray applied in an up-stroke pattern over the muscles and occiput to the vertex; for the splenius cervicis, the spray should also cover the angle of the shoulder and the lateral aspect of the head as far forward as the eye (protect the eye from spray)
- Operator grasps the head between both hands, applies upward traction, and gently further flexes and rotates the head toward the opposite side to take up slack
- Patient simultaneously looks down, slowly exhales, and may actively tilt the head in the direction of the stretch (reciprocal inhibition)
- Hot pack applied promptly over treated muscles
TrPs also respond to pressure release and deep massage.
Trigger Point Injection
Splenius capitis injection requires extreme caution.
The exposed vertebral artery lies craniad to the C₁ spinous process.
Corrective Actions
Postural:
- Keep head and neck erect, thoracic spine extended; minimise excessive twisting and turning
- Monitor/display screen directly in front of the body, at an angle that encourages erect posture; documents at the same level as the monitor, not flat on the desk to one side
- Body asymmetry (lower limb length inequality, small hemipelvis) should be corrected
- Avoid an excessively long walking cane
- Sleep with the head and neck in a neutral position with appropriate pillow support
Environmental:
- Keep the neck warm by sleeping in a high-necked sleeping garment, wearing a turtleneck sweater or scarf during waking hours, and avoiding cold drafts
Exercise therapy:
- Patient releases tightness by reaching up (as in Fig. 16.11A of the source volume) and gently flexing and turning the head through the full range of flexion, extension, and rotation — best done sitting on a stool or standing in a warm shower
- After release, the head and neck are moved slowly and gently through the full range three times
- If adjacent fibres remain sore and taut, the exercise is repeated with slightly different head positions to engage fibres that still feel uncomfortable
- Avoid "head rolling" (swinging the head around the full range of motion) — this seriously overloads adjacent lines of taut muscle fibres and can worsen the condition
Satellite Trigger Points
- Levator scapulae — frequently co-active; active TrPs rarely appear in the splenii alone
- Semispinalis capitis — primary synergist for extension
- Semispinalis cervicis — primary synergist for extension
- Upper trapezius — synergist for contralateral rotation
- Sternocleidomastoid — synergist for rotation; frequently co-involved after whiplash
Related Pages
- Pain:Vertex Headache — Diagnostic algorithm including splenius capitis as primary source
- Pain:Occipital — Overlapping referral from splenius cervicis and suboccipital muscles
- Pain:Orbital — Craniad splenius capitis TrP referral to the orbit
- Muscle:Splenius Cervicis — Companion muscle, treated together
- Muscle:Levator Scapulae — Consistently co-active
- Muscle:Semispinalis Capitis — Primary synergist, deep to splenius capitis
- Muscle:Sternocleidomastoid — Frequent whiplash co-involvement
References
- Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 15.